Can We Keep Feeding the World?

Just ahead of the UN General Assembly meetings in New York, the UN World Food Programme has put out a report on world hunger, and it is not good news:

After steadily declining for over a decade, global hunger is on the rise again, affecting 815 million people in 2016, or 11 per cent of the global population, says a new edition of the annual United Nations report on world food security and nutrition released today. At the same time, multiple forms of malnutrition are threatening the health of millions worldwide. 

The increase – 38 million more people than the previous year – is largely due to the proliferation of violent conflicts and climate-related shocks, according to The State of Food Security and Nutrition in the World 2017.

The climate shocks are particularly noteworthy since they seem to be getting worse and, in most respects, it will be a bigger job to change human behavior regarding our polluting of the world's atmosphere than to tamp down violent conflicts. Consider a paper just published in the Proceedings of the National Academy of Science by climate researchers at UC San Diego and Texas A&M, and summarized for us non-climate scientists yesterday by the San Diego Union-Tribune:

There’s a very small but distinct possibility that rapid global warming could pose an “existential threat” to the survival of humans by 2050, UC San Diego said Thursday in one of the most dire forecasts yet about climate change. The school’s Scripps Institution of Oceanography published a paper that said there is a 5 percent chance of catastrophic change within roughly three decades, and a smaller chance that it would broadly wipe out human life. Scripps made the claim while proposing two new classifications for climate change: catastrophic and unknown, or existential. Catastrophic means that most people would have trouble adapting to such change. The latter terms means that they would not be able to.

“Other people have used the word catastrophic, but I have resisted doing so until now,” said the study’s lead author, Veerabhadran Ramanathan, a renowned climate scientist who helped influence Pope Francis to urge the world to fight global warming in 2015.
“I changed my mind because, over the past five years, I have gone back and reviewed data that we began collecting from satellites in the 1980s and data from aircraft and changes in the intensity of storms, and studies about the possible health affects of rapid global warming. “There is a low probability that the change will be catastrophic. But you would not get on an airplane if you thought there was a 5 percent chance that it was going to crash.” He noted that the probability of an existential threat is even smaller, but said, “that chance rises to 20 to 30 percent by 2070.”

These climate changes call into question our ability to continue feeding a population that is still growing and still consuming more calories per person, especially when agriculture itself contributes to climate change in a variety of ways through deforestation, methane gas production, and the increasing diversion of water for agricultural purposes. Are we already in a situation of global overshoot?