Terrestrial biosphere response to rising CO2 and temperatureby Jonathan DuHamel on Dec. 06, 2012, under Climate change, General Science
Rise of global temperature and increasing carbon dioxide content of the atmosphere are predicted by the Intergovernmental Panel on Climate Change (IPCC) and other climate alarmists to cause all kinds of undesirable consequences. However, a review of the peer-reviewed scientific literature shows that terrestrial productivity is responding very positively and the planet is greening.
The Center for the Study of Carbon Dioxide and Global Change has a new report which refutes claims that global warming is stressing Earth’s natural and agro-ecosystems by reducing plant growth and development. The report,”The State of Earth’s Terrestrial Biosphere” (133 pages, 2.3Mb) is a meta-analysis, a review, of nearly 400 peer-reviewed scientific studies examining how the productivity of Earth’s plants have responded to the 20th and now 21st century rise in global temperature and atmospheric CO2.
The productivity of the planet’s terrestrial biosphere, on the whole, has been increasing with time, revealing a great greening of the Earth that extends throughout the entire globe. Satellite-based analyses of net terrestrial primary productivity (NPP) reveal an increase of around 6-13% since the 1980s.
There is no empirical evidence to support the model-based claim that future carbon uptake by plants will diminish on a global scale due to rising temperatures. In fact, just the opposite situation has been observed in the real world. Earth’s land surfaces were a net source of CO2-carbon to the atmosphere until about 1940. From 1940 onward, however, the terrestrial biosphere has become,
in the mean, an increasingly greater sink for CO2-carbon. Over the past 50 years, for example, global carbon uptake has doubled from 2.4 ± 0.8 billion tons in 1960 to 5.0 ± 0.9 billion tons in 2010.
The observed global greening has occurred in spite of all the many real and imagined assaults on Earth’s vegetation that have occurred over the past several decades, including wildfires, disease, pest outbreaks, deforestation, and climatic changes in temperature and precipitation, more than compensating for any of the negative effects these phenomena may have had on the global biosphere.
There is compelling evidence that the atmosphere’s rising CO2 content is most likely the primary cause of the observed greening trends.
In the future, Earth’s plants should be able to successfully adjust their physiology to accommodate a warming of the magnitude and rate-of-rise that is typically predicted by climate models to accompany the projected future increase in the air’s CO2 content. Factoring in plant productivity gains that will occur as a result of the aerial fertilization effect of the ongoing rise in atmospheric CO2, plus its accompanying transpiration reducing effect that boosts plant water use efficiency, the world’s vegetation possesses an ideal mix of abilities to reap a tremendous benefit in the years and decades to come.