Drought Drives Decade-Long Decline in Plant Growth

[GliderGuider]

I don't tremember this being posted, even though it's from 2010. It puts the lie to the "CO2 is plant food" bleat from the deniers...

Drought Drives Decade-Long Decline in Plant Growth

Earth has done an ecological about-face: Global plant productivity that once flourished under warming temperatures and a lengthened growing season is now on the decline, struck by the stress of drought.

NASA-funded researchers Maosheng Zhao and Steven Running, of the University of Montana in Missoula, discovered the global shift during an analysis of NASA satellite data. Compared with a six-percent increase spanning two earlier decades, the recent ten-year decline is slight -- just one percent. The shift, however, could impact food security, biofuels, and the global carbon cycle.

Conventional wisdom based on previous research held that land plant productivity was on the rise. A 2003 paper in Science led by then University of Montana scientist Ramakrishna Nemani (now at NASA Ames Research Center, Moffett Field, Calif.) showed that global terrestrial plant productivity increased as much as six percent between 1982 and 1999. That's because for nearly two decades, temperature, solar radiation and water availability -- influenced by climate change -- were favorable for growth.

Setting out to update that analysis, Zhao and Running expected to see similar results as global average temperatures have continued to climb. Instead, they found that the impact of regional drought overwhelmed the positive influence of a longer growing season, driving down global plant productivity between 2000 and 2009. The team published their findings Aug. 20 (GG: 2010) in Science.

[Socialistlemur]

1. Plant growth increase stalled with temperature increase stall

Surface temperatures stopped increasing around 12 to 13 years ago. This matches the stall in plant growth and it does confirm the warmer and the more CO2 the better for plants. For now anyway..the article has a slight mistake because global surface temperature isn't climbing.

[Iterate]

2. And that gets you Number 9 on the list.

99 One-Liners Rebutting Denier Talking Points — With Links To The Full Climate Science
http://thinkprogress.org/climate/2013/05/07/1972581/99-one-liners-rebutting-denier-talking-points-with-links-to-the-full-climate-science/

“It hasn’t warmed since 1998″

For global records, 2010 is the hottest year on record, tied with 2005.

The planet has continued to accumulate heat since 1998 – global warming is still happening. Nevertheless, surface temperatures show much internal variability due to heat exchange between the ocean and atmosphere. 1998 was an unusually hot year due to a strong El Nino

And that in turn links here:
What has global warming done since 1998?
http://www.skepticalscience.com/global-warming-stopped-in-1998.htm

Any more?

[GliderGuider]

3. They're talking about regional droughts

Plants grow in particular places, after all. I wouldn't expect globally averaged air temperatures to be as significant as regional changes in water patterns or the other factors they mention..

Zhao and Running's analysis showed that since 2000, high-latitude northern hemisphere ecosystems have continued to benefit from warmer temperatures and a longer growing season. But that effect was offset by warming-associated drought that limited growth in the southern hemisphere, resulting in a net global loss of land productivity.

"This past decade’s net decline in terrestrial productivity illustrates that a complex interplay between temperature, rainfall, cloudiness, and carbon dioxide, probably in combination with other factors such as nutrients and land management, will determine future patterns and trends in productivity," Wickland said.