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'Abrupt thaw' of permafrost beneath lakes could significantly affect climate change models

Leah Lawrence -

Methane released by thawing permafrost from some Arctic lakes could significantly accelerate climate change, according to a new University of Alaska Fairbanks-led study.

The study, which was published Aug. 15 in the journal Nature Communications, focuses on the carbon released by thawing permafrost beneath thermokarst lakes. Such lakes develop when warming soil melts ground ice, causing the surface to collapse and form pools of water. Those pools accelerate permafrost thaw beneath the expanding lakes, providing food for microbes that produce the greenhouse gases carbon dioxide and methane.

Lead author Katey Walter Anthony and her colleagues studied hundreds of thermokarst lakes in Alaska and Siberia during a 12-year period, measuring their growth and how much methane was bubbling to their surface. By combining field work results with remote-sensing data of lake changes during the past two years, they determined the "abrupt thaw" beneath such lakes is likely to release large amounts of permafrost carbon into the atmosphere this century. The lake activity could potentially double the release from terrestrial landscapes by the 2050s.

The effort, conducted by a team of U.S. and German researchers, is part of a 10-year NASA-funded project to better understand climate change effects on the Arctic. Additional support by the National Science Foundation allowed scientists from UAF and the Alaska Division of Geological and Geophysical Surveys to collect data on permafrost location, thaw and associated greenhouse gas release from lakes in Interior Alaska's Goldstream Valley.

The researchers found the release of greenhouse gases beneath thermokarst lakes is relatively rapid, with deep thawing taking place over the course of decades. Permafrost in terrestrial environments generally experiences shallow seasonal thawing over longer time spans. The release of that surface permafrost soil carbon is often offset by an increased growth in vegetation.

"Thermokarst lakes provide a completely different scenario. When the lakes form, they flash-thaw these permafrost areas," said Walter Anthony, an associate professor with UAF's Water and Environmental Research Center. "Instead of centimeters of thaw, which is common for terrestrial environments, we've seen 15 meters of thaw beneath newly formed lakes in Goldstream Valley within the past 60 years."

Emissions from thermokarst lakes aren't currently factored into global climate models because their small size makes individual lakes difficult to include. However, the study's authors show that these lakes are hotspots of permafrost carbon release. They argue that not including them in global climate models overlooks their feedback effect, which occurs when the release of greenhouse gases from permafrost increases warming. That feedback is significant because methane is about 30 times more potent than carbon dioxide as a heat-trapping gas.

Existing models currently attribute about 20 percent of the permafrost carbon feedback this century to methane, with the rest due to carbon dioxide from terrestrial soils. By including thermokarst lakes, methane becomes the dominant driver, responsible for 70 to 80 percent of permafrost carbon-caused warming this century. Adding thermokarst methane to the models makes the feedback's effect similar to that of land-use change, which is the second-largest source of human-made warming.

Unlike shallow, gradual thawing of terrestrial permafrost, the abrupt thaw beneath thermokarst lakes is irreversible this century. Even climate models that project only moderate warming this century will have to factor in their emissions, according to the study.

"You can't stop the release of carbon from these lakes once they form," Walter Anthony said. "We cannot get around this source of warming."

Story Source: University of Alaska Fairbanks.



Astronomers identify some of the oldest galaxies in the universe

Stephen Cho -

Astronomers from the Institute for Computational Cosmology at Durham University and the Harvard-Smithsonian Center for Astrophysics, have found evidence that the faintest satellite galaxies orbiting our own Milky Way galaxy are amongst the very first galaxies that formed in our Universe.

Scientists working on this research have described the finding as "hugely exciting" explaining that that finding some of the Universe's earliest galaxies orbiting the Milky Way is "equivalent to finding the remains of the first humans that inhabited the Earth."

The research group's findings suggest that galaxies including Segue-1, Bootes I, Tucana II and Ursa Major I are in fact some of the first galaxies ever formed, thought to be over 13 billion years old.

When the Universe was about 380,000 years old, the very first atoms formed. These were hydrogen atoms, the simplest element in the periodic table. These atoms collected into clouds and began to cool gradually and settle into the small clumps or "halos" of dark matter that emerged from the Big Bang.

This cooling phase, known as the "Cosmic dark ages," lasted about 100 million years. Eventually, the gas that had cooled inside the halos became unstable and began to form stars -- these objects are the very first galaxies ever to have formed.

With the formation of the first galaxies, the Universe burst into light, bringing the cosmic dark ages to an end.

Dr Sownak Bose, at Harvard-Smithsonian Center for Astrophysics, working with Dr Alis Deason and Professor Carlos Frenk at Durham University's ICC, identified two populations of satellite galaxies orbiting the Milky Way.

The first was a very faint population consisting of the galaxies that formed during the "cosmic dark ages." The second was a slightly brighter population consisting of galaxies that formed hundreds of millions of years later, once the hydrogen that had been ionized by the intense ultraviolet radiation emitted by the first stars was able to cool into more massive dark matter halos.

Remarkably, the team found that a model of galaxy formation that they had developed previously agreed perfectly with the data, allowing them to infer the formation times of the satellite galaxies.

Their findings are published in the Astrophysical Journal.

Professor Carlos Frenk, Director of Durham University's Institute for Computational Cosmology, said: "Finding some of the very first galaxies that formed in our Universe orbiting in the Milky Way's own backyard is the astronomical equivalent of finding the remains of the first humans that inhabited the Earth. It is hugely exciting.

"Our finding supports the current model for the evolution of our Universe, the 'Lambda-cold-dark-matter model' in which the elementary particles that make up the dark matter drive cosmic evolution."

The intense ultraviolet radiation emitted by the first galaxies destroyed the remaining hydrogen atoms by ionizing them (knocking out their electrons), making it difficult for this gas to cool and form new stars.

The process of galaxy formation ground to a halt and no new galaxies were able to form for the next billion years or so.

Eventually, the halos of dark matter became so massive that even ionized gas was able to cool. Galaxy formation resumed, culminating in the formation of spectacular bright galaxies like our own Milky Way.

Dr Sownak Bose, who was a PhD student at the ICC when this work began and is now a research fellow at the Harvard-Smithsonian Center for Astrophysics, said: "A nice aspect of this work is that it highlights the complementarity between the predictions of a theoretical model and real data.

"A decade ago, the faintest galaxies in the vicinity of the Milky Way would have gone under the radar. With the increasing sensitivity of present and future galaxy censuses, a whole new trove of the tiniest galaxies has come into the light, allowing us to test theoretical models in new regimes."

Dr Alis Deason, who is a Royal Society University Research Fellow at the ICC, Durham University, said: "This is a wonderful example of how observations of the tiniest dwarf galaxies residing in our own Milky Way can be used to learn about the early Universe."

Dr Bose is supported through an Institute for Theory and Computation fellowship at Harvard University, whilst Dr Deason is supported by a Royal Society University Research Fellowship. Professor Carlos Frenk and Dr Deason are both supported by the Science and Technology Facilities Council Consolidated Grant for Astronomy and Durham University.



Climate change: How do we know? NASA




This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO2 has increased since the Industrial Revolution. (Credit: Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record.)




The Earth's climate has changed throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era — and of human civilization. Most of these climate changes are attributed to very small variations in Earth’s orbit that change the amount of solar energy our planet receives.


Scientific evidence for warming of the climate system is unequivocal.


- Intergovernmental Panel on Climate Change


The current warming trend is of particular significance because most of it is very likely human-induced and proceeding at a rate that is unprecedented in the past 1,300 years.1


Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting many different types of information about our planet and its climate on a global scale. This body of data, collected over many years, reveals the signals of a changing climate.


The heat-trapping nature of carbon dioxide and other gases was demonstrated in the mid-19th century.2 Their ability to affect the transfer of infrared energy through the atmosphere is the scientific basis of many instruments flown by NASA. There is no question that increased levels of greenhouse gases must cause the Earth to warm in response.


Ice cores drawn from Greenland, Antarctica, and tropical mountain glaciers show that the Earth’s climate responds to changes in greenhouse gas levels. They also show that in the past, large changes in climate have happened very quickly, geologically-speaking: in tens of years, not in millions or even thousands.3


The evidence for rapid climate change is compelling:


Sea level rise


Global sea level rose about 17 centimeters (6.7 inches) in the last century. The rate in the last decade, however, is nearly double that of the last century.4


Global temperature rise


All three major global surface temperature reconstructions show that Earth has warmed since 1880.5 Most of this warming has occurred since the 1970s, with the 20 warmest years having occurred since 1981 and with all 10 of the warmest years occurring in the past 12 years.6 Even though the 2000s witnessed a solar output decline resulting in an unusually deep solar minimum in 2007-2009, surface temperatures continue to increase..7


Warming oceans


The oceans have absorbed much of this increased heat, with the top 700 meters (about 2,300 feet) of ocean showing warming of 0.302 degrees Fahrenheit since 1969.8


Shrinking ice sheets


The Greenland and Antarctic ice sheets have decreased in mass. Data from NASA's Gravity Recovery and Climate Experiment show Greenland lost 150 to 250 cubic kilometers (36 to 60 cubic miles) of ice per year between 2002 and 2006, while Antarctica lost about 152 cubic kilometers (36 cubic miles) of ice between 2002 and 2005.


Declining Arctic sea ice


Both the extent and thickness of Arctic sea ice has declined rapidly over the last several decades.9


Glacial retreat


Glaciers are retreating almost everywhere around the world — including in the Alps, Himalayas, Andes, Rockies, Alaska and Africa.10 


Extreme events


The number of record high temperature events in the United States has been increasing, while the number of record low temperature events has been decreasing, since 1950. The U.S. has also witnessed increasing numbers of intense rainfall events.11


Ocean acidification


Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30 percent.12,13 This increase is the result of humans emitting more carbon dioxide into the atmosphere and hence more being absorbed into the oceans. The amount of carbon dioxide absorbed by the upper layer of the oceans is increasing by about 2 billion tons per year.14,15


Decreased snow cover


Satellite observations reveal that the amount of spring snow cover in the Northern Hemisphere has decreased over the past five decades and that the snow is melting earlier.16


July 2017 equaled record July 2016


NASA's Goddard Institute for Space Studies


A global map of the June 2017 LOTI (land-ocean temperature index) anomaly, relative to the 1951-1980 June average. View larger image.

A global map of the June 2017 LOTI (land-ocean temperature index) anomaly, relative to the 1951-1980 June average. View larger image.


July 2017 was statistically tied with July 2016 as the warmest July in the 137 years of modern record-keeping, according to a monthly analysis of global temperatures by scientists at NASA's Goddard Institute for Space Studies (GISS) in New York.


Last month was about 0.83 degrees Celsius warmer than the mean July temperature of the 1951-1980 period. Only July 2016 showed a similarly high temperature (0.82 °C), all previous months of July were more than a tenth of a degree cooler.


The GISTEMP monthly temperature anomalies superimposed on a 1980-2015 mean seasonal cycle. The GISTEMP monthly temperature anomalies superimposed on a 1980-2015 mean seasonal cycle. View larger image or PDF.


Starting with this update, the previously used ocean data set ERSST v4 was replaced by the newer ERSST v5. This contributed to the changes of some of the data in last month's update. For more information, see the Updates to Analysis and the History Pages.


The monthly analysis by the GISS team is assembled from publicly available data acquired by about 6,300 meteorological stations around the world, ship- and buoy-based instruments measuring sea surface temperature, and Antarctic research stations.


The modern global temperature record begins around 1880 because previous observations didn't cover enough of the planet. Monthly analyses are sometimes updated when additional data becomes available, and the results are subject to change.




2016 marks three consecutive years of record warmth for the globe -

With a boost from El Nino, 2016 began with a bang. For eight consecutive months, January to August, the globe experienced record warm heat.  With this as a catalyst, the 2016 globally averaged surface temperature ended as the highest since record keeping began in 1880, according to scientists from NOAA's National Centers for Environmental Information (NCEI).

The average temperature across global land and ocean surfaces in 2016 was 58.69 degrees F or 1.69 degrees F above the 20th century average. This surpassed last year’s record by 0.07 degrees F. Since the start of the 21st century, the annual global temperature record has been broken five times (2005, 2010, 2014, 2015, and 2016).

Despite the cooling influence of a weak La Nina in the latter part of the year, the year ended with the third warmest December on record for the globe, with an average temperature 1.42 degrees F above the 20th century average.  

In a separate analysis of global temperature data released at the same time, scientists from NASA also found 2016 to be the warmest year on record.  

More noteworthy findings from 2016:

  • The globally averaged sea surface temperature was the highest on record, 1.35 degree F above average.
  • The globally averaged land surface temperature was the highest on record, 2.57 degrees F above average. 
  • North America had its warmest year on record; South America and Africa had their second; Asia and Europe had their third; and Australia had its fifth.
  • The average Arctic sea ice extent for the year was 3.92 million square miles, the smallest annual average since record-keeping began in 1979. 
  • The average Antarctic sea ice extent for the year was 4.31 million square miles, the second smallest annual average since record-keeping began in 1979.



2016’s Arctic Report Card: Temperatures Went Crazy - By Kristy Hamilton 10/01/2017, 13:11


The Arctic continues to impress us – for all the wrong reasons. Just before Christmas, another surge of winter warmth blanketed the region, an unwelcome end to an already crazy year. 


A week before the holidays, Arctic temperatures rose 16.7 to 27.7°C (30 to 50°F) above average. The ice, in turn, melted to an all-time low in seven of the 11 months on record.


All this matters. As scientists continue to tell us: What happens in the Arctic, does not stay in the Arctic. Changes there result in a cascade of consequences around the globe.


"We've seen a year in 2016 in the Arctic like we've never seen before," said Jeremy Mathis, director of NOAA’s Arctic research program. The polar region showed "a stronger, more pronounced signal of persistent warming than any other year in our observation record."


In fact, the Arctic is warming twice as fast as the rest of the planet. The North Pole and much of the surrounding ocean will soon be ice-free in the summer for the first time in thousands of years. In less than 25 years, human will possibly be able to sail across the Arctic in summer.


"The records are astounding because there are so many of them," said Jennifer Francis in an interview with Scientific American. "The extra warming that is happening up in the Arctic – the 'Arctic amplification' – has been the greatest we’ve ever seen." 


In a bon voyage to 2016, here’s a highlight reel of the madness that went on in the Arctic. 


A bad start - First and foremost, the year began on a low note: January sea ice extent was the lowest on satellite record, with some regions warming an incredible 8°C (14°F) above average.


Double trouble - The Arctic warmed twice as fast as the rest of the planet, reaching 3.5°C (6.3°F) above average since 1900.


An early melt - The Greenland ice sheet began melting much too early – the second earliest in the 37-year observational record.


Winter is coming… or so we thought - November reached an incredible 20°C (36°F) above normal. In fact, in the middle of the month, ice extent actually decreased for several days.


MAYbe it gets worse - May snow cover came in at a record low since satellite observations began, with less than 4 million square kilometers (1.5 million square miles). This allowed more sunlight to reach the upper layers of the ocean, stimulating widespread algae blooms.


Slipping away - Arctic sea ice extent was the lowest on satellite record from mid-October 2016 to late November 2016, with 28 percent less than the average for October.


Warming waters  - Sea surface temperatures in August reached 5°C (9°F) warmer than the 1982-2010 August mean in the Barents and Chukchi seas, as well as off the east and west coasts of Greenland.


Setting records… again and again - Seven out of the 12 months reached an all-time record low for sea ice cover. The winners of this unfortunate honor go to January, February, April, May, June, October, and November. 


The above facts are from the Arctic Report Card 2016, a peer-reviewed report in its 11th year that brought together 61 scientists from 11 nations. 


"The 2016 Arctic Report Card further documents the unraveling of the Arctic and the crumbling of the pillars of the global climate system that the Arctic maintains,” said Rafe Pomerance, chair of the group Arctic 21 and Polar Research Board of the National Academy of Sciences.



2016 was 2nd warmest year on record for U.S. -

To understand how, here’s our U.S. “climate by the numbers” summary for 2016: 

Full year, January through December

The average U.S. temperature in 2016 was 54.9 degrees F (2.9 degrees F above average), which ranked as the second warmest year in 122 years of record-keeping. This is the 20th consecutive year the annual average temperature exceeded the average. Every state in the contiguous U.S. and Alaska experienced above-average annual temperatures, according to scientists from NOAA’s National Centers for Environmental Information.

Precipitation for the year totaled 31.70 inches, ranking as the 24th wettest year. The national drought footprint expanded from about 18 percent in January to about 23 percent by the end of December. At just under 19 percent, the average area of drought in the U.S. for 2016 was the smallest since 2010.


The month of December was near the long-term average for the month with an average temperature across the contiguous U.S. of 32.9 degrees F, 0.17 degrees above average. The northwestern quarter of the contiguous U.S. was generally cooler than average for the month, while the southern U.S. and the Atlantic Coast states were warmer than average. The precipitation total for the month was 0.34 inch above normal.

Here's a look at the locations of 15 billion-dollar disasters that occurred in the U.S. in 2016. (NOAA NCEI)

Billion-dollar disasters 

Deadly, extreme weather caused major loss of life and damage in 2016. 

Last year, the U.S. experienced 15 weather and climate disasters, each with losses exceeding $1 billion for a total of $46 billion. Tragically, the disasters claimed a total of 138 lives:

       1 drought (affected multiple areas);

    1 wildfire (affected multiple areas); 
    4 inland floods;
    8 severe storms; and
    1 hurricane (Matthew).

This is the second highest number of disasters experienced in one year, with double the record number of inland flooding events for one year.

Since 1980, the U.S. has sustained more than 200 weather and climate disasters that exceeded $1.1 trillion in overall damages. 

More: Find NOAA’s climate reports on and download images at the NCEI climate monitoring website



U.S. had its warmest autumn and 2nd warmest November on record -

The average U.S. temperature in autumn was 57.6 degrees F (4.1 degrees above average) and surpassed last fall as the warmest on record, according to scientists from NOAA’s National Centers for Environmental Information. Precipitation during this period was about average for the nation, with wet extremes in the Northwest and dry extremes in the Central Rockies, Gulf Coast region and interior Southeast.

The month of November was the 2nd warmest on record, with an average temperature across the contiguous U.S. of 48 degrees F, 6.3 degrees above average. Every state in the Continental U.S. and Alaska were warmer than average during November. The precipitation total for the month was 0.50 inch below average. 

The year-to-date (January-November) average temperature for the contiguous U.S. was 56.9 degrees F, 3.1 degrees above average. All Lower 48 states and Alaska observed above-average temperatures during this 11-month period. Precipitation during this time was 1.37 inches above normal.   

Other noteworthy November climate event include: 

  • Drought: The area of extreme to exceptional drought in the Lower 48 increased from 4.9% to 8.7%; in the Southeast it nearly doubled from 19.7% to 36.2%. 
  • Wildfires: In November, 8,560 wildfires raged across the Continental U.S. and burned more than 275,000 acres, most notably in the Southeast.
  • North Dakota experienced temperatures 12.8 degrees F above average, nearly 2 degrees above the previous record set in 1999.
  • Alaska experienced its warmest year to date on record, a full 6 degrees F above average.
  • Pacific Northwest experienced above-normal precipitation during autumn along the coast. Washington state was record wet. 


September 2016 was Warmest on Record by Narrow Margin

October 18th, 2016 by Michael Cabbage & Leslie McCarthy

September 2016 was the warmest September in 136 years of modern record-keeping, according to a monthly analysis of global temperatures by scientists at NASA’s Goddard Institute for Space Studies (GISS) in New York.

September 2016’s temperature was a razor-thin 0.004 degrees Celsius warmer than the previous warmest September in 2014. The margin is so narrow those two months are in a statistical tie. Last month was 0.91 degrees Celsius warmer than the mean September temperature from 1951-1980.

The record-warm September means 11 of the past 12 consecutive months dating back to October 2015 have set new monthly high-temperature records. Updates to the input data have meant that June 2016, previously reported to have been the warmest June on record, is, in GISS’s updated analysis, the third warmest June behind 2015 and 1998 after receiving additional temperature readings from Antarctica. The late reports lowered the June 2016 anomaly by 0.05 degrees Celsius to 0.75.

“Monthly rankings are sensitive to updates in the record, and our latest update to mid-winter readings from the South Pole has changed the ranking for June,” said GISS director Gavin Schmidt. “We continue to stress that while monthly rankings are newsworthy, they are not nearly as important as long-term trends.”

The monthly analysis by the GISS team is assembled from publicly available data acquired by about 6,300 meteorological stations around the world, ship- and buoy-based instruments measuring sea surface temperature, and Antarctic research stations. The modern global temperature record begins around 1880 because previous observations didn’t cover enough of the planet. Monthly analyses are updated when additional data become available, and the results are subject to change.

Related Links
+ For more information on NASA GISS’s monthly temperature analysis, visit:

+ For more information about how the GISS analysis compares to other global analysis of global temperatures, visit:

+ To learn more about climate change and global warming, visit:

The last three Octobers are the warmest on record

NASA's Goddard Institute for Space Studies

A map of the October 2016 LOTI (land-ocean temperature index) anomaly, showing that the Arctic region was much warmer than average. The United States and North Africa were also relatively warm. The largest area of cooler temperatures stretched across Russia.

October 2016 was the second warmest October in 136 years of modern record-keeping, according to a monthly analysis of global temperatures by scientists at NASA's Goddard Institute for Space Studies (GISS) in New York. 

October 2016's temperature was 0.18 degrees Celsius cooler than the warmest October in 2015. Last month was 0.89 degrees Celsius warmer than the mean October temperature from 1951-1980.

The top three October temperature anomalies have been the past three years. 2015 was the hottest on record, 1.07 degrees Celsius warmer than the October mean temperature, followed by 2016 and 2014. The top 10 October temperature anomalies all have occurred since 2000.

“We continue to stress that long-term trends are the important thing, much more so than monthly rankings,” said GISS director Gavin Schmidt.

Monthly temperature anomalies with base 1980-2015, superimposed on a 1980-2015 mean seasonal cycle. Credit: NASA/GISS/Schmidt.

The monthly analysis by the GISS team is assembled from publicly available data acquired by about 6,300 meteorological stations around the world, ship- and buoy-based instruments measuring sea surface temperature, and Antarctic research stations.

The modern global temperature record begins around 1880 because previous observations didn't cover enough of the planet. Monthly analyses are sometimes updated when additional data becomes available, and the results are subject to change.

Related links

For more information on NASA GISS's monthly temperature analysis, visit

For more information about NASA GISS, visit

Media contacts

Michael Cabbage
NASA's Goddard Institute for Space Studies, New York, N.Y.

Leslie McCarthy
NASA's Goddard Institute for Space Studies, New York, N.Y.


2016 locked into being hottest year on record, NASA says - The Guardian, US Edition

Data shows September was the warmest in modern temperature monitoring following months of record-breaking anomalies this year

Tuesday 18 October 2016 09.45 EDT

Nasa has all but declared this year to be the hottest yet recorded, after September narrowly turned out the warmest in modern temperature monitoring.

Last month was 0.91C above the average temperature for that time of year from 1951 to 1980, the benchmark used for measuring rises.

The new findings follow record-breaking monthly anomalies throughout this year, leading the agency to believe that because of the highs reported so far, 2016 will take the crown as warmest in the 136 years of modern data-keeping.

Dr Gavin Schmidt, director of Nasa’s Goddard Institute for Space Studies, tweeted:

Last month was only just over the previous record, coming in at a razor-thin 0.004C above the previous high for the time of year, reached in September 2014. That tiny margin may be revised in future, as monthly temperature data can be nudged up or down retrospectively as later reports come in. For instance, June 2016 was initially reported as the warmest on record but was subsequently revised downward slightly to the third warmest.

But it makes the trend for the year, and the long-term decadal trends, easier to discern. September’s high temperatures compared with the long-term average means that 11 of the last 12 consecutive months, back to October 2015, have set new records.

Last year was the hottest year since modern records began, brought about in part by a strong El Niño event, a Pacific weather system that can affect sea and air temperatures around the world, but also by strong underlying trends. Schmidt said earlier this year, when 2015’s status was confirmed, that it would have been the warmest year even without the El Niño.

July 2016 was the hottest single month since instruments have been reliably used to measure temperature, followed by a similar effect in August.

This year’s heat has continued to be affected by the tail-end of the El Niño weather phenomenon, as although the system has now dissipated, air temperatures tend to lag behind by several months.

If a new temperature record is set for 2016, it will confirm the longer term trends of climate change. This in turn will help scientists to counter claims from global warming sceptics that the rise in global temperatures has “paused” and therefore that climate change is not a threat.

The monthly reports from Nasa come from publicly available data from about 6,300 meteorological stations around the world, as well as measurements taken from ships and buoys at sea, and Antarctic research stations.

Other agencies, including the UK’s Met Office, the US National Oceanic and Atmospheric Administration and Japan’s Meteorological Agency, also publish temperature estimates. The Met Office forecast last December that this year would be the hottest ever, based on its observations. Also closely watched is the World Meteorological Organisation, which in July made a prediction that this year would be the hottest, based on data available to that date.

Final confirmation of whether this year is record-breaking is likely to come early next year.

Arctic conditions may become critical for polar bears by end of 21st century

University of Washington,

Shifts in the timing and duration of ice cover, especially the possible lengthening of ice-free periods, may impact polar bears under projected warming before the end of the 21st century, according to a study published November 26, 2014 in the open-access journal PLOS ONE by Stephen Hamilton from University of Alberta and colleagues.

Sea ice across the Arctic is declining and altering physical characteristics of marine ecosystems, and polar bears are vulnerable to these changes in sea ice conditions. The authors of this study used sea ice projections for the Canadian Arctic Archipelago from 2006-2100 and metrics developed from polar bear energetics modeling to gain insight into the conservation challenges for polar bears facing habitat loss.

Shifts away from multiyear ice to annual ice cover throughout the region, as well as lengthening ice-free periods, may become critical for polar bears before the end of the 21st century with projected warming. Each polar bear population in the Archipelago may undergo 2-5 months of ice-free conditions, where no such conditions exist presently. Under business-as-usual climate projections, polar bears may face starvation and reproductive failure across the entire Archipelago by the year 2100. "We predict that nearly one-tenth of the world's polar bear habitat, as much as one-quarter of their global population, may undergo significant habitat loss under business-as-usual climate projections," said Stephen Hamilton.




Land-based food not nutritionally sufficient for wild polar bears, according to new study

American Museum of Natural History,

A study, by San Diego Zoo Global conservationists, released this week (Sept. 12, 2016) is shedding new light on how scientists evaluate polar bear diet and weight loss during their fasting season. On average, a polar bear loses up to 30 percent of its total body mass while fasting during the open-water season. Although some scientists previously believed land-based foods could supplement the bears' nutritional needs until the sea ice returns, a new study published in the scientific journal Physiological and Biochemical Zoology has revealed that access to terrestrial food is not sufficient to reduce the rate of body mass loss for fasting polar bears.

The study -- undertaken by Manitoba Sustainable Development, the University of Alberta, and Environment and Climate Change Canada -- weighed polar bears that were detained in the Polar Bear Holding Facility in Churchill, Manitoba, Canada from 2009 to 2014. Polar bears were kept in this facility as part of the Polar Bear Alert Program, which aims to reduce conflict between humans and polar bears around the town of Churchill. To prevent habituation, polar bears are not fed while in the facility, which allowed for a controlled measure of their weight loss. On average, polar bears lost 2.2 pounds (1 kilogram) of mass per day -- exactly the same amount as free-ranging bears measured during the ice-free season on the coastline of Hudson Bay. Scientists reported that even with land-based food opportunities, polar bears lost the same amount of weight.

"Some studies have suggested that polar bears could adapt to land-based foods to offset the missing calories during a shortened hunting period on the ice," said Nicholas Pilfold, Ph. D., lead author of the study and a postdoctoral associate in Applied Animal Ecology at San Diego Zoo Global. "Yet, our results contradict this, as unfed polar bears in our study lost mass at the same rate as free-ranging bears that had access to land-based food."

Researchers also estimated starvation timelines for adult males and sub-adults, and found that sub-adults were more likely to starve before their adult counterparts. "Sub-adult polar bears have lower fat stores, and the added energy demands associated with growth," said Pilfold, "Future reductions to on-ice hunting opportunities due to sea ice loss will affect the younger polar bears first -- especially given that these bears are less-experienced hunters."

Today, it is estimated that there are approximately 26,000 polar bears throughout the Arctic. The Western Hudson Bay subpopulation of polar bears is currently stable, as the length of the ice-free season has shown recent short-term stability. However, past increases in the length of the ice-free season have caused declines in the number of bears, with sub-adults having a higher mortality rate than adults. The current research helps to shed light on the mechanisms of past population declines, as well as to provide an indication of what may occur if sea ice declines again.

For nearly a decade, San Diego Zoo Global researchers and its U.S. and Canadian partners have focused on developing conservation strategies to boost wild populations of polar bears. At the San Diego Zoo, polar bears "collaborated" with researchers at the U.S. Geological Survey in Alaska by wearing an accelerometer collar to track their movements. The data gained from accelerometers on collared polar bears -- at the Zoo and in the Arctic -- will provide scientists with new insights into the bears' daily behavior, movements and energy needs, and a better understanding of the effects of climate change on polar bears.




Polar bears unlikely to thrive on land-based foods

American Museum of Natural History,

A team of scientists led by the U.S. Geological Survey found that polar bears, increasingly forced on shore due to sea ice loss, may be eating terrestrial foods including berries, birds and eggs, but any nutritional gains are limited to a few individuals and likely cannot compensate for lost opportunities to consume their traditional, lipid-rich prey -- ice seals.

"Although some polar bears may eat terrestrial foods, there is no evidence the behavior is widespread," said Dr. Karyn Rode, lead author of the study and scientist with the USGS. "In the regions where terrestrial feeding by polar bears has been documented, polar bear body condition and survival rates have declined."

The authors detail their findings in a review article in Frontiers in Ecology and the Environment. The scientists noted that over much of the polar bear's range, terrestrial habitats are already occupied by grizzly bears. Those grizzly bears occur at low densities and are some of the smallest of their species due to low food quality and availability. Further, they are a potential competitor as polar bears displaced from their sea ice habitats increasingly use the same land habitats as grizzly bears.

"The smaller size and low population density of grizzly bears in the Arctic provides a clear indication of the nutritional limitations of onshore habitats for supporting large bodied polar bears in meaningful numbers," said Rode. "Grizzly bears and polar bears are likely to increasingly interact and potentially compete for terrestrial resources."

The study found that fewer than 30 individual polar bears have been observed consuming bird eggs from any one population, which typically range from 900 to 2000 individuals. "There has been a fair bit of publicity about polar bears consuming bird eggs. However, this behavior is not yet common, and is unlikely to have population-level impacts on trends in body condition and survival," said Rode.

Few foods are as energetically dense as marine prey. Studies suggest that polar bears consume the highest lipid diet of any species, which provides all essential nutrients and is ideal for maximizing fat deposition and minimizing energetic requirements. Potential foods found in the terrestrial environment are dominated by high-protein, low-fat animals and vegetation. Polar bears are not physiologically suited to digest plants, and it would be difficult for them to ingest the volumes that would be required to support their large body size.

"The reports of terrestrial feeding by polar bears provide important insights into the ecology of bears on land," said Rode. "In this paper, we tried to put those observations into a broader context. Focused research will help us determine whether terrestrial foods could contribute to polar bear nutrition despite the physiological and nutritional limitations and the low availability of most terrestrial food resources. However, the evidence thus far suggests that increased consumption of terrestrial foods by polar bears is unlikely to offset declines in body condition and survival resulting from sea ice loss."




All polar bears across the Arctic face shorter sea ice season

NASA/Goddard Space Flight Center,

It's no secret that Arctic sea ice is melting.

Polar bears, the poster-child for climate change, are among the animals most affected by the seasonal and year-to-year changes in Arctic sea ice, because they rely on this surface for essential activities such as hunting, traveling and breeding.

A new University of Washington study, with funding and satellite data from NASA and other agencies, finds a trend toward earlier sea ice melt in the spring and later ice growth in the fall across all 19 polar bear populations, which can negatively impact the feeding and breeding capabilities of the bears. The paper, to appear Sept. 14 in The Cryosphere, is the first to quantify the sea ice changes in each polar bear subpopulation across the entire Arctic region using metrics that are specifically relevant to polar bear biology.

"This study shows declining sea ice for all subpopulations of polar bears," said co-author Harry Stern, a researcher with the UW's Polar Science Center. "We have used the same metric across all of the polar bear subpopulations in the Arctic so we can compare and contrast, for example, the Hudson Bay region with the Baffin Bay region using the same metric."

The analysis shows that the critical timing of the sea ice break-up and sea ice freeze-up is changing in all areas in a direction that is harmful for polar bears.

Nineteen separate polar bear populations live throughout the Arctic, spending their winters and springs roaming on sea ice and hunting. The bears have evolved mainly to eat seals, which provide necessary fats and nutrients in the harsh Arctic environment. Polar bears can't outswim their prey, so instead they perch on the ice as a platform and ambush seals at breathing holes or break through the ice to access their dens.

"Sea ice really is their platform for life," said co-author Kristin Laidre, a researcher at the UW's Polar Science Center. "They are capable of existing on land for part of the year, but the sea ice is where they obtain their main prey."

The new study draws upon 35 years of satellite data showing sea ice concentration each day in the Arctic. NASA scientists process the data, stored at the National Snow and Ice Data Center in Boulder, Colorado.

The center also reports each fall the yearly minimum low for Arctic sea ice. This August saw the fourth lowest in the satellite record.

Across all 19 polar bear populations, the researchers found that the total number of ice-covered days declined at the rate of seven to 19 days per decade between 1979 and 2014. Sea ice concentration during the summer months -- an important measure because summertime is when some subpopulations are forced to fast on land -- also declined in all regions, by 1 percent to 9 percent per decade.

The most striking result, researchers said, is the consistent trend across all polar bear regions for an earlier spring ice melt and a later fall freeze-up. Arctic sea ice retreats in the springtime as daylight reappears and temperatures warm. In the fall months the ice sheets build again as temperatures drop.

"These spring and fall transitions bound the period when there is good ice habitat available for bears to feed," Laidre said. "Those periods are also tied to the breeding season when bears find mates, and when females come out of their maternity dens with very small cubs and haven't eaten for months."

The researchers found that on average, spring melting was three to nine days earlier per decade, and fall freeze-up was three to nine days later per decade. That corresponds to a roughly 3 ½ week shift at either end -- and seven weeks of total loss of good sea ice habitat for polar bears -- over the 35 years of Arctic sea ice data.

"We expect that if the trends continue, compared with today, polar bears will experience another six to seven weeks of ice-free periods by mid-century," Stern said. The trend appears to be linear and isn't accelerating or leveling off, Stern added. The researchers recommend that the National Climate Assessment incorporate the timing of spring ice retreat and fall ice advance as measures of climate change in future reports.

The study's results currently are used by the International Union for Conservation of Nature's polar bear specialist group, which completes assessments of polar bears and issues the species' conservation status. The researchers plan to update their findings each year as new ice coverage data are available.

"It's nice to see this work being used in high-level conservation goals," Laidre said.





How a Few Species Are Hacking Climate Change

 European larger banded snails (Cepaea nemoralis) with light colored shells are becoming more prevalent over time in the Netherlands.

As the Earth heats up, animals and plants are not necessarily helpless. They can move to cooler climes; they can stay put and adapt as individuals to their warmer environment, and they can even adapt as a species, by evolving.

The big question is, will they be able to do any of that quickly enough? Most researchers believe that climate change is happening too fast for many species to keep up. (Related: "Rain Forest Plants Race to Outrun Global Warming.")

But in recent weeks, the general gloom has been pierced by two rays of hope: Reports have come in of unexpected adaptive ability in endangered butterflies in California and in corals in the Pacific.

Two isolated reports don't, of course, diminish the gravity of the global threat. But they do highlight how little we still know about nature's ability to cope with climate change.

"Most of the models that ecologists are putting out are assuming that there's no adaptive capacity. And that's silly," says Ary Hoffmann, a geneticist at the University of Melbourne in Australia and the co-author of an influential review of climate change-related evolution. "Organisms are not static."

That species are on the move is becoming obvious not just to scientists but also to gardeners and nature-lovers everywhere. Butterflies are living higher up on mountains; trees are moving north in North America and Europe. In North Carolina, residents are still agog at encountering nine-banded armadillos, which have invaded the state from the south.

A 2011 review of data on hundreds of moving species found a median shift to higher altitudes of 36 feet (11 meters) per decade and a median shift to higher latitudes of about 10.5 miles (17 kilometers) per decade.

There's also a clear warming-related trend in the timing of natural events. One study suggests that spring shifted 1.7 days earlier between 1954 and 2007. Insects are emerging earlier; birds are nesting earlier; plants are flowering and leafing out earlier. The latest of such natural events studies, out last month, shows that climate change has stretched out the wildflower bloom season in Colorado by 35 days.

The report last month from a butterfly conference in England was a bit different, however. It concerned the endangered quino checkerspot butterfly (Euphydryas editha quino), well known for being threatened by climate change. Many experts believed the species was doomed unless humans collected the butterflies and moved them north; their path to higher ground seemed to be blocked by the megalopolis of Los Angeles.

But at the conference, according to an account in the Guardian, Camille Parmesan of the Marine Sciences Institute at Plymouth University in the U.K., who has studied the quino checkerspot for years, reported that it had miraculously shifted its range to higher altitudes. Furthermore, it had somehow learned to lay its eggs on a new host plant.

"Every butterfly biologist who knew anything about the quino in the mid-1990s thought it would be extinct by now, including me," Parmesan told the Guardian. (Parmesan confirmed the account for National Geographic, but declined to elaborate until she could publish her own research paper on the subject.)

Another uplifting tale of unexpected resilience appeared in Science on April 24. While surveying the waters of the future National Park of American Samoa off Ofu Island, researcher Peter Craig noticed isolated coral pools that were considerably warmer than the rest. High water temperatures can cause corals to "bleach": They spit out the photosynthesizing algae that live inside them, thereby losing both their color and their means of collecting energy. Yet these particular corals didn't seem to be suffering too much from the heat.

Marine ecologist Stephen Palumbi of Stanford University in California tested the heat tolerance of some of theAcropora hyacinthus corals from unusually hot pools. He plopped them into a container, then cranked up the heat inside to 34 degrees Celsius (93 degrees Fahrenheit) for three hours. Just 20 percent of the individual coral animals spit out their algae, whereas 55 percent of coral from an otherwise similar but much cooler pool spit out their algae during the test.

The more revealing test came next. Palumbi took corals from the cool pool and put them in the hot pool. One year later, he measured their heat tolerance—and found it had greatly improved. The heat stress test caused only 32.5 percent of the transplanted corals to spit out their algae, instead of 55 percent.

Palumbi's experiment helped tease out the two different mechanisms by which organisms can adapt. Individual transplanted corals were able to adapt to the hotter water, without any change in their genes. Biologists call that phenotypic plasticity.

But the transplanted corals were still not as good at taking the heat as corals that were native to the hot pools; 32.5 percent of them bleached during the stress test, compared with just 20 percent of the hot-pool natives. That gap might reflect the operation of another mechanism of adaptation: genetic evolution. Over many generations, natural selection may have changed the genes of corals in the hot pools by allowing the most heat-tolerant ones to survive and produce more offspring.

For the Samoan corals in a warming ocean, the combination of plastic adaptation and genetic evolution could be "the difference between dead and more or less unfazed," Palumbi says. The results suggest to him that previous predictions of extinction for all coral might be a bit too pessimistic.

More generally, such individual stories of adaptive ability suggest that the quality of resilience has been left out of our models and predictions about how the natural world will respond to climate change. "I do think there is more hidden adaptability out there," says Palumbi.

Snails, Salmon, Owls, and Thyme

So far, evidence of adaptability is available for only a few species. Juha Merilä of the University of Helsinki in Finland, who edited a special issue of the journal Evolutionary Applications in January rounding up the evidence for such changes, guesses that there are perhaps 20 studies robustly linking adaptation through phenotypic plasticity to climate change, and another 20 or so clearly linking climate change with genetic evolution. But, he says, it's likely that this is a tiny fraction of the species in which adaptation is occurring.

There are better data on shifts in ranges and the timing of events, thanks in part to citizen science efforts like Project Budburst and the Great Backyard Bird Count. But these studies don't prove whether the shifts are due to plasticity or genes, or even that climate change is the underlying cause—they're just highly suggestive correlations between rising temperatures and the location and behavior of species.

Among the most solid examples of actual evolution in response to climate change is a shift in the proportion of European larger banded snails (Cepaea nemoralis) with light colored shells. Shell color is genetic, and the genes responsible are known. It has been shown that, in a given environment, snails with light colored shells have a lower body temperature than those with dark colored shells. And light colored shells are becoming more prevalent over time in the Netherlands, even in wooded, shady environments where you might expect dark shells to dominate.

A few other studies have caught species actually evolving in response to climate change. Pink salmon in Auke Creek, Alaska, which is heating up .03 degrees Celsius (.054 degrees Fahrenheit) per year, are now migrating out of the creek earlier, and scientists have shown that that change is genetic.

Wild thyme (Thymus vulgaris) in France has evolved in response to fewer extreme cold events since the 1970s, producing more pungent oils to deter herbivores (at the cost of becoming less cold-hardy).

Tawny owls (Strix aluco) can be light gray or brown, depending on the genes they inherit from their parents. As snow cover in Finland has declined since the late 1970s, the light gray owls, best camouflaged during snow, no longer have much of an advantage, and scientists have shown that brown owls are now much more common.

Such studies require patience. "It is really hard to get the evidence because you need long-term studies and it is very hard to make science over these kinds of periods," says Merilä. The snails have been studied for at least 45 years, the owls for 36, and the salmon for 32.

And such studies also leave unresolved how one ought to feel about these subtle transformations. When we see spring springing earlier or snails changing color, should we mourn the changes as sad, human-caused degradation, or embrace them as evidence of plucky nature fighting back? "A bit of both," says Hoffmann. "We have to accept that things will change."

"I think we should feel impressed by the impact that we have, that we can change the course of evolution around us by the way we change the environment," says Menno Schilthuizen, who studies how invertebrates adapt to climate change at the Naturalis Biodiversity Center in Leiden, Netherlands. "Our impact is much further and deeper than we tend to think."

Researchers on this topic are quick to point out that evolution and individual plasticity won't save all species. Climate change is happening too fast, they say, for some species to survive.

Hypotheses abound on which species are likely to keep up with climate change. Species with short lives, like fruit flies, have more generations in which to evolve, compared with long-lived species that don't begin to breed for decades. And some species, like some conifer trees, simply have more gene variants to work with in their populations.

Conversely, long-lived species with low genetic variability—including many rare mammals—will have less adaptive ability. "In general, you might expect that weedy, short-lived species and ones that are able to disperse widely might be favored," says Steven Franks, who studies how plants adapt to climate change at Fordham University in New York.

There's also a widespread but still poorly tested hypothesis that tropical species may have a harder time evolving than temperate species do. Having evolved in a region with less climate variability over both the years and the millennia, tropical species may harbor a less diverse set of genes related to heat tolerance and similar traits. "The tropics are hot, but they are not particularly variable," Hoffmann says. "It is not like they are being challenged all the time."

Predicting which species will survive on their own can help researchers zero in on which species might benefit most from human help. A key goal of such an intervention would be to bring back genetic diversity to small, isolated populations so that evolution has something to work with. "Where we have a fragmented landscape, we should connect it up again, restore the flow," says Hoffmann. "We are restoring a process, and that process is really powerful."

Where it's not possible to connect fragmented populations with contiguous habitat, "restoring the flow" could mean moving seeds or individuals from population to population. In dire cases, Hoffmann says, conservationists might want to create hybrids of two related species or subspecies, if each one is insufficiently able to adapt on its own. "People think 'genetic pollution!'" he says. "But you could achieve a lot in terms of saving these populations."

Palumbi, meanwhile, thinks the adaptability he found in Samoan corals won't save them as much as provide a grace period; eventually, he says, human-made climate change could outstrip the corals'—and many other species'—ability to adapt.

"That delay of a couple of decades is the good news here," he says. "Let's use the decades to solve the problem." And when he says "the problem," he means the root of the problem: carbon emissions.



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