Some climate alarmists have been claiming that global warming has been decreasing agricultural productivity. (For instance, see here.) But real data proves otherwise.
Carbon dioxide (CO2) is plant food. Increasing CO2 and warming have enhanced plant growth and makes plants more water-efficient.
And, according to NASA, “greening of the Earth mitigates surface warming” (Link). NASA writes: “A new study reports that increased vegetation growth during the recent decades, known as the ‘Greening Earth’, has a strong cooling effect on the land due to increased efficiency of heat and water vapor transfer to the atmosphere.” This is based upon satellite observations.
The Heartland Institute has created a new website (Climate at a Glance) which “puts frequently argued climate issues into short, concise, summaries that provide the most important, accurate, powerful information.) Their section on crop production begins:
“Longer growing seasons, higher temperatures, and more atmospheric carbon dioxide are creating ideal crop conditions. As global climate modestly warms, the U.S. and global crop yields are setting new records almost every year.
The same is true for nearly all other nations, too. Thanks in large part to longer growing seasons, fewer frost events, more precipitation, and the fertilization effect of atmospheric carbon dioxide, farmers are producing more food on less land, allowing them to feed a growing global population.” (Read more)
The Center for the Study of Carbon Dioxide and Global Change provides summaries and reviews of scientific papers.
Here are the conclusions of their summary studies of plant productivity:
Distant and historic past:
In spite of claims that rising atmospheric CO2 concentrations and unprecedented global warming since the inception of the Industrial Revolution are destroying (or will destroy) the productivity of the biosphere, the terrestrial vegetative biomass of the globe as a whole continues to rise; and it appears to be doing so at a remarkable rate.
As for why is this so, it may well be that the twin evils of the radical environmental movement (rising temperatures and atmospheric CO2 concentrations) are not the evils they are made out to be, but actually blessings in disguise … blessings that are fueling the biosphere!
In spite of climate-alarmist claims that the temperatures of the latter part of the 20th century and on through the present were unprecedented over the past one to two millennia (which is highly debatable) and that atmospheric CO2 concentrations were the highest they had been for several hundred millennia (which is true), as well as the fact that mankind yearly harvests and/or destroys much of the planet’s natural vegetation, the total yearly production of terrestrial vegetative biomass for the globe as a whole continues to rise, and at a remarkable rate.
Projection for the future:
Throughout the course of the current century, even the severe warming predicted by current climate models will not likely be detrimental to plant growth and productivity.
Rather, it will likely be a major benefit, enhancing plant growth and soil organic carbon storage, which (in addition to their own virtues) will provide significant negative feedback to global warming as the Greening of the Earth continues!
A review of papers on grasslands finds “as the air’s CO2 concentration continues to increase, grassland species should respond positively by exhibiting increased rates of photosynthesis.
“In addition, such increases in photosynthesis will likely occur even under unfavorable growing conditions characterized by less-than-adequate soil moisture, inadequate soil nutrition, elevated air temperature, and physical stress imposed by herbivory.
“Thus, Earth’s grassland species will likely grow ever more robustly in the future, thanks to the ever-increasing atmospheric CO2 concentration produced by the burning of ever-larger quantities of fossil fuels.”
The studies above are on plant productivity in general. More specific studies on food crops show enhanced growth with warming temperatures and increases in carbon dioxide.
Written by Jonathan DuHamel