In next 50 years, humans must produce as much food as has been produced in history

The head of Australia's national science organization said climate change -- global warming to some -- poses a threat to the future of global food production.

The head of Australia's national science organization said climate change -- global warming to some -- poses a threat to the future of global food production.

In an Australian Broadcasting Corp. report, the chief executive of the Australian Commonwealth Scientific and Research Organization, Megan Clark, warns that higher prices on water and continued agricultural carbon emissions will make it difficult to sustain the world's growing population.

Clark said to the National Press Club in Canberra that the amount of food needed over the next 50 years is far more than could ever be imagined.

"It is really hard for me to comprehend that in the next 50 years, we'll have to produce as much food as we have ever produced in human history," Clark said. "That means in the working life of my children as much grain as has ever been harvested since the Egyptian time."

This isn't the first time such a claim has been made and supported. In 2006, NASA warned that the warming of the Earth's climate reduces the ocean's primary food supply, posing a threat to fisheries and ecosystems.

As the climate warms, ocean plants called phytoplankton growth rates decline, dragging down the amount of carbon dioxide they consume. From there, it's a slippery slope: with reduced carbon dioxide consumption, the gas accumulates more rapidly in the atmosphere, in turn spurring more warming.

Cornell professor David Pintimel explains, in notes from a forum in 1993:

By 2030, according to one scenario, atmospheric carbon dioxide concentrations will be double pre-industrial concentrations, other greenhouse gases will increase substantially, and temperatures in North America and Africa will rise approximately 2 degrees Centigrade.

If these changes occur, projected average rainfall in central North America will be 10 percent lower than now; in eastern and northern Africa, it may be 10 percent higher. While more rain holds the promise of increasing African agricultural productivity, higher temperatures may offset this advantage by decreasing soil moisture. As a result, dry agricultural regions may continue to suffer the effects of inadequate water supplies, even if levels of rainfall increase.

The challenge, Pintimel writes, is to slow the change, since a severe shift is catastrophic to ecosystems. "Slow change also may enable natural biota to adapt," Pintimel writes. "However, even a minor change (for example, one-tenth of a degree per decade) could spark significant changes in the frequency of climate extremes, including heat waves, floods, and droughts."

This post was originally published on Smartplanet.com