Annals of global warming: NASA finds amplified greenhouse effects shift northern growing seasons

March 11, 2013

Global warming affects plants in northern hemisphere, NASA chart

From NASA: Of the 10 million square miles (26 million square kilometers) of northern vegetated lands, 34 to 41 percent showed increases in plant growth (green and blue), 3 to 5 percent showed decreases in plant growth (orange and red), and 51 to 62 percent showed no changes (yellow) over the past 30 years. Satellite data in this visualization are from the AVHRR and MODIS instruments, which contribute to a vegetation index that allows researchers to track changes in plant growth over large areas. Credit: NASA’s Goddard Space Flight Center Scientific Visualization Studio; click image for original view; click here for greater detail

Press release from NASA, March 10, 2013 (links in text added here):

RELEASE : 13-069

 

Amplified Greenhouse Effect Shifts North’s Growing Seasons

WASHINGTON — Vegetation growth at Earth’s northern latitudes increasingly resembles lusher latitudes to the south, according to a NASA-funded study based on a 30-year record of land surface and newly improved satellite data sets.

An international team of university and NASA scientists examined the relationship between changes in surface temperature and vegetation growth from 45 degrees north latitude to the Arctic Ocean. Results show temperature and vegetation growth at northern latitudes now resemble those found 4 degrees to 6 degrees of latitude farther south as recently as 1982.

“Higher northern latitudes are getting warmer, Arctic sea ice and the duration of snow cover are diminishing, the growing season is getting longer and plants are growing more,” said Ranga Myneni of Boston University’s Department of Earth and Environment. “In the north’s Arctic and boreal areas, the characteristics of the seasons are changing, leading to great disruptions for plants and related ecosystems.”

The study was published Sunday in the journal Nature Climate Change.

Myneni and colleagues used satellite data to quantify vegetation changes at different latitudes from 1982 to 2011. Data used in this study came from NOAA’s Advanced Very High Resolution Radiometers (AVHRR) onboard a series of polar-orbiting satellites and NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on the Terra and Aqua satellites.

As a result of enhanced warming and a longer growing season, large patches of vigorously productive vegetation now span a third of the northern landscape, or more than 3.5 million square miles (9 million square kilometers). That is an area about equal to the contiguous United States. This landscape resembles what was found 250 to 430 miles (400 to 700 kilometers) to the south in 1982.

“It’s like Winnipeg, Manitoba, moving to Minneapolis-Saint Paul in only 30 years,” said co-author Compton Tucker of NASA’s Goddard Space Flight Center in Greenbelt, Md.

The Arctic’s greenness is visible on the ground as an increasing abundance of tall shrubs and trees in locations all over the circumpolar Arctic. Greening in the adjacent boreal areas is more pronounced in Eurasia than in North America.

An amplified greenhouse effect is driving the changes, according to Myneni. Increased concentrations of heat-trapping gasses, such as water vapor, carbon dioxide and methane, cause Earth’s surface, ocean and lower atmosphere to warm. Warming reduces the extent of polar sea ice and snow cover, and, in turn, the darker ocean and land surfaces absorb more solar energy, thus further heating the air above them.

“This sets in motion a cycle of positive reinforcement between warming and loss of sea ice and snow cover, which we call the amplified greenhouse effect,” Myneni said. “The greenhouse effect could be further amplified in the future as soils in the north thaw, releasing potentially significant amounts of carbon dioxide and methane.”

To find out what is in store for future decades, the team analyzed 17 climate models. These models show that increased temperatures in Arctic and boreal regions would be the equivalent of a 20-degree latitude shift by the end of this century relative to a period of comparison from 1951-1980.

However, researchers say plant growth in the north may not continue on its current trajectory. The ramifications of an amplified greenhouse effect, such as frequent forest fires, outbreak of pest infestations and summertime droughts, may slow plant growth.

Also, warmer temperatures alone in the boreal zone do not guarantee more plant growth, which also depends on the availability of water and sunlight.

“Satellite data identify areas in the boreal zone that are warmer and dryer and ¬¬other areas that are warmer and wetter,” said co-author Ramakrishna Nemani of NASA’s Ames Research Center in Moffett Field, Calif. “Only the warmer and wetter areas support more growth.”

Researchers did find found more plant growth in the boreal zone from 1982 to 1992 than from 1992 to 2011, because water limitations were encountered in the latter two decades.

Data, results and computer codes from this study will be made available on NASA Earth Exchange (NEX), a collaborative supercomputing facility at Ames. NEX is designed to bring scientists together with data, models and computing resources to accelerate research and innovation and provide transparency.

For more information and images associated with this release, visit:

http://go.nasa.gov/12Amv2s

– end –


text-only version of this release

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Annals of Global Warming: NASA film, Piecing Together the Temperature Puzzle

March 5, 2012

NASA describes the film, “Piecing Together the Temperature Puzzle”:

The past decade has been the hottest ever recorded since global temperature records began 150 years ago. This video discusses the impacts of the sun’s energy, Earth’s reflectance and greenhouse gasses on global warming.
Credit: NASA
Vital Signs of the Planet: Global Climate Change and Global Warming. Current news and data streams about global warming and climate change from NASA.

Vodpod videos no longer available.

Piecing Together the Temperature Puzzle, posted with vodpod

More NASA climate films, here, at Climate Reel.


Annals of global warming: NASA press release, 2010 tied as warmest year on record

December 31, 2011

Certain things need to be on the record, in the annals.  Last January I failed to post this press release from NASA, issued January 11, 2011:

NASA Research Finds 2010 Tied for Warmest Year on Record

01.12.11
WASHINGTON — Global surface temperatures in 2010 tied 2005 as the warmest on record, according to an analysis released Wednesday by researchers at NASA’s Goddard Institute for Space Studies (GISS) in New York.

The two years differed by less than 0.018 degrees Fahrenheit. The difference is smaller than the uncertainty in comparing the temperatures of recent years, putting them into a statistical tie. In the new analysis, the next warmest years are 1998, 2002, 2003, 2006, 2007 and 2009, which are statistically tied for third warmest year. The GISS records begin in 1880.

The analysis found 2010 approximately 1.13 F warmer than the average global surface temperature from 1951 to 1980. To measure climate change, scientists look at long-term trends. The temperature trend, including data from 2010, shows the climate has warmed by approximately 0.36 F per decade since the late 1970s.

“If the warming trend continues, as is expected, if greenhouse gases continue to increase, the 2010 record will not stand for long,” said James Hansen, the director of GISS.

The analysis produced at GISS is compiled from weather data from more than 1000 meteorological stations around the world, satellite observations of sea surface temperature and Antarctic research station measurements. A computer program uses the data to calculate temperature anomalies — the difference between surface temperature in a given month and the average temperature for the same period during 1951 to 1980. This three-decade period acts as a baseline for the analysis.

The resulting temperature record closely matches others independently produced by the Met Office Hadley Centre in the United Kingdom and the National Oceanic and Atmospheric Administration’s National Climatic Data Center.

The record temperature in 2010 is particularly noteworthy, because the last half of the year was marked by a transition to strong La Niña conditions, which bring cool sea surface temperatures to the eastern tropical Pacific Ocean.

“Global temperature is rising as fast in the past decade as in the prior two decades, despite year-to-year fluctuations associated with the El Niño-La Niña cycle of tropical ocean temperature,” Hansen and colleagues reported in the Dec. 14, 2010, issue of Reviews of Geophysics.

A chilly spell also struck this winter across northern Europe. The event may have been influenced by the decline of Arctic sea ice and could be linked to warming temperatures at more northern latitudes.

Arctic sea ice acts like a blanket, insulating the atmosphere from the ocean’s heat. Take away that blanket, and the heat can escape into the atmosphere, increasing local surface temperatures. Regions in northeast Canada were more than 18 degrees warmer than normal in December.

The loss of sea ice may also be driving Arctic air into the middle latitudes. Winter weather patterns are notoriously chaotic, and the GISS analysis finds seven of the last 10 European winters warmer than the average from 1951 to 1980. The unusual cold in the past two winters has caused scientists to begin to speculate about a potential connection to sea ice changes.

“One possibility is that the heat source due to open water in Hudson Bay affected Arctic wind patterns, with a seesaw pattern that has Arctic air downstream pouring into Europe,” Hansen said.

For more information about GISS’s surface temperature record, visit:
http://data.giss.nasa.gov/gistemp/

A Warming World
http://climate.nasa.gov/warmingworld/

Global Temperatures Animation
http://svs.gsfc.nasa.gov/vis/a000000/a003600/a003674/index.html


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