A study in Nature has confirmed what to many non-climate-scientists is probably blindingly obvious: far from being traumatised by global warming, plants simply adapt to it.
Here’s the abstract of the study, lead authored by Professor Peter Reich, an ecologist and plant physiologist from the University of Minnesota.
Boreal and temperate trees show strong acclimation of respiration to warming
Plant respiration results in an annual flux of carbon dioxide (CO2) to the atmosphere that is six times as large as that due to the emissions from fossil fuel burning, so changes in either will impact future climate. As plant respiration responds positively to temperature, a warming world may result in additional respiratory CO2 release, and hence further atmospheric warming. Plant respiration can acclimate to altered temperatures, however, weakening the positive feedback of plant respiration to rising global air temperature, but a lack of evidence on long-term (weeks to years) acclimation to climate warming in field settings currently hinders realistic predictions of respiratory release of CO2 under future climatic conditions. Here we demonstrate strong acclimation of leaf respiration to both experimental warming and seasonal temperature variation for juveniles of ten North American tree species growing for several years in forest conditions. Plants grown and measured at 3.4 °C above ambient temperature increased leaf respiration by an average of 5% compared to plants grown and measured at ambient temperature; without acclimation, these increases would have been 23%. Thus, acclimation eliminated 80% of the expected increase in leaf respiration of non-acclimated plants. Acclimation of leaf respiration per degree temperature change was similar for experimental warming and seasonal temperature variation. Moreover, the observed increase in leaf respiration per degree increase in temperature was less than half as large as the average reported for previous studies, which were conducted largely over shorter time scales in laboratory settings. If such dampening effects of leaf thermal acclimation occur generally, the increase in respiration rates of terrestrial plants in response to climate warming may be less than predicted, and thus may not raise atmospheric CO2 concentrations as much as anticipated.
Some previous alarmist studies have suggested that global warming will create a positive feedback loop, whereby plants exposed to more heat will increase their production of carbon dioxide, making the planet even warmer still. If you believe in anthropogenic warming theory, this would indeed be a scary prospect given that plants produce six times more CO2 than humans produce by burning fossil fuels.
As the Nature press release puts it:
For every 10 degrees Celsius of temperature increase, plants are known to double their rate of metabolism, which has led to fears that global warming will trigger a positive-feedback loop, switching plants from being a net carbon dioxide sink — absorbing more carbon dioxide than they release — to becoming a net source of the warming gas.
However the study found that this wasn’t the case.
They found that 10 types of North American trees, in artificially heated outdoor forest plots, adapted to higher temperatures without drastically boosting the amount of carbon produced by their leaves.
“Plants play less of a role than previously thought in speeding up global warming through accelerated respiratory carbon dioxide emissions,” lead author Peter Reich of the University of Minnesota told an online news conference. “Given the number of plants on Earth this is a big deal,” he said of their role in the carbon cycle.
Plants aren’t bothered by warmer weather and adapt to changing conditions. Who would ever have imagined it?
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