You know, because a tiny increase in the global temperatures since 1850 are super bad
Climate Change Likely to Slow Plant Growth in Northern Hemisphere
Plants are a highly effective carbon sink. Globally, forests absorb about 7.6 billion metric tons of carbon dioxide per year, about 1.5 times the annual emissions of the United States.
Since the 1980s, climate warming, prompted by rising levels of carbon dioxide and other greenhouse gasses in the atmosphere, has caused an increase in plant productivity in the Northern Hemisphere outside the tropics.
But new research published May 30 in Nature Climate Change estimates that summer warming in this region will begin to have the opposite effect within the next half-century, causing photosynthesis—or plant productivity—to decline. The global land carbon sink will likely take a hit as a result, the authors write.
The researchers found that generally in the Northern Hemisphere, warmer temperatures will mean less summer plant productivity by 2070 for most regions below 60° N—the approximate latitude of Oslo, Norway, and Anchorage, Alaska. Plant productivity in Arctic areas, however, will continue rising as the temperature increases.
Doom!
Scientists used two different ways of estimating the effects of rising summer temperatures on productivity: models that represent photosynthesis based on a variety of environmental factors, and climate models combined with extrapolations from historical observations of the thermal tolerance of wild plants. Anping Chen, a study coauthor and ecologist at Colorado State University, explains in an email that researchers rely more on the first method because it takes into account factors like elevated CO2 levels, changes in precipitation, and the acclimation of plants to warming.
Using eight Earth system models, the study found that under intermediate projected emissions conditions, about 48 percent of vegetated land in the Northern Hemisphere will experience a decline in plant productivity due to warming by 2060, rising to 78 percent by the end of this century.
And there they are, the computer models, typical doom prognostications. So, just wondering, if this turns out to be wrong, who is held responsible? Oh, right, these are far in the future, so, no one will remember.
Read: Too Much Plant Food Likely To Slow Plant Growth Or Something »