Agricultural Yields Already Suffering With Climate Change

We really haven't noticed it yet, but climate change is 
cutting into agricultural yields, and the problem will
keep worsening as the world warms. 

There aren't any big worldwide food shortages, at least not yet, due to climate change, but a new study suggests we are definitely heading in the wrong direction.  

According to Preventionweb.net:

"Global agricultural productivity has declined by about 21 percent in the last 60 years as a result of climate change - the equivalent of seven years' lost production - a study has found. 

The decrease was most pronounced in warm regions such as Africa (30 percent) and Latin America and the Caribbean (26 percent) according to research published in Nature Climate Change, which looked at data from 1961 to 2020."

The seeming disconnect behind what seems to be adequate food supply and lost production is explained this way:

"Ariel Ortiz-Bobea, professor of applied economics at Cornell University and lead author of the study, told SciDev.Net: 'These numbers don't mean that we are producing less than we did back in 1961 - we've actually produced more year after year. Instead, our study is saying that global agricultural productivity is almost 21 percent lower than it could have been in a world without climate change.'"

Improvements in productivity have helped keep up yields, but it's not translating to resilience to climate change. 

There are considerations that the study might not have entirely taken into account. Per Preventionweb.net:

"This research doesn't consider small-scale agriculture which persists in different parts of the world, like Africa and Latin America, probably because this type of production is usually not included in official records," said Carolina Greta-Sanchez of the Center of Atmospheric Sciences at the National Autonomous University of Mexico. 

Other research is similar to the one I described above. 

A June New Scientist article has this to say:

"Rising global temperatures are likely to cause deep losses to the world's most important crops - despite farmers' best efforts to adapt. A global analysis to crop yields suggests that, by the end of the century, each degree Celsius of warming will reduce the food available per person any about 121 kilocalories a day. 

Under a 3 degree Celsius scenario - roughly our current trajectory - 'that works out to giving up breakfast for everyone,' says Andrew Hultgren at the University of Illinois Urbana-Champagne."

The research cited in New Scientist said the six main global staple crops. They found that all crops except rice would suffer in a hotter world. (Rice crops like hotter nights) 

An example of the projected reduced crop yields with climate change is corn. Yields would fall by 12 to 28 percent by the end of the century, depending on whether greenhouse gasses rise moderately or very quickly. 

The number these researchers came up with take into account how farmers would adapt to hotter temperatures, and the fact crops might be fertilized a bit because of higher carbon dioxide levels in the atmosphere.