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

More:


Gradient Sun, NASA video for classroom use

October 21, 2012

Real science often is more fantastic that the stuff people make up. Haldane was right.

Still shot from NASA solar gradient video

Not the Sun you’re used to seeing.

In a century our studies of the Sun progressed from the deep calculations based on erroneous assumptions of what our star is make of  (Lord Kelvin‘s calculations on how long the iron in the Sun would take to cool to its present color), to today’s solar studies, in which nearly every moment of the Sun’s life is recorded through a half dozen different sensors, by satellites and telescopes and whatever other means we have to capture data from the Sun’s burning.

It’s hard science — but it borders on art, too, doesn’t it?  Watch this:

Gradient Sun [HD Video], originally uploaded by NASA Goddard Photo and Video.

What’s going on here?

Via Flickr:

Watching a particularly beautiful movie of the sun helps show how the lines between science and art can sometimes blur. But there is more to the connection between the two disciplines: science and art techniques are often quite similar, indeed one may inform the other or be improved based on lessons from the other arena. One such case is a technique known as a “gradient filter” – recognizable to many people as an option available on a photo-editing program. Gradients are, in fact, a mathematical description that highlights the places of greatest physical change in space. A gradient filter, in turn, enhances places of contrast, making them all the more obviously different, a useful tool when adjusting photos. Scientists, too, use gradient filters to enhance contrast, using them to accentuate fine structures that might otherwise be lost in the background noise. On the sun, for example, scientists wish to study a phenomenon known as coronal loops, which are giant arcs of solar material constrained to travel along that particular path by the magnetic fields in the sun’s atmosphere. Observations of the loops, which can be more or less tangled and complex during different phases of the sun’s 11-year activity cycle, can help researchers understand what’s happening with the sun’s complex magnetic fields, fields that can also power great eruptions on the sun such as solar flares or coronal mass ejections.

The images here show an unfiltered image from the sun next to one that has been processed using a gradient filter. Note how the coronal loops are sharp and defined, making them all the more easy to study. On the other hand, gradients also make great art. Watch the movie to see how the sharp loops on the sun next to the more fuzzy areas in the lower solar atmosphere provide a dazzling show.

NASA/Goddard Space Flight Center

NASA/Goddard Space Flight Center

To download this video go to: svs.gsfc.nasa.gov/goto?11112

NASA image use policy.

NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission.

Follow us on Twitter

Like us on Facebook

Find us on Instagram

Teachers ought to figure out how to use this in classrooms — and I don’t mean astronomy, physics and chemistry only.  Can you find a use for this film in geography?  History? English and literature?

Sometime shortly after World War II scientists captured film of a mass coronal ejection from the Sun.  You probably can imagine the film I’m remembering.  That snippet found its way into films students saw in science, geography, chemistry, biology (“this is our Sun, from which all living things get energy, through photosynthesis”), and probably a half dozen other subjects.  It was spectacular, and it was just about all that was available for classroom use, then.  Students now probably have never seen it.  Worse, my experience is that students in high school generally have very little familiarity with the science projects carried out by agencies like NASA and the National Science Foundation, and they know very little about the Sun, or the Moon and other planets.

Teachers, the state isn’t going to help you put this into your classrooms.  Can you figure out some way to get it in?

More:


%d bloggers like this: