This section of the World Economic Forum’s 2016 Global Risk Report explains in a fair amount of detail how climate change is likely to cause food shortages.

The risk to food security is especially great because agriculture is already straining to meet a rapidly growing demand from a finite resource base. The combined impact of a rising population and growth of the middle class – wealthier people eat more cereal-intensive meat – is set to drive a demand increase of 60% by 2050.³Yet the global average yield growth for cereals has slowed in recent years; it already lags behind demand growth. This gap cannot be covered by an expansion of cropland because of the need to protect forests and other areas of high value for conservation and carbon sequestration. Agriculture is increasingly competing with other uses for land – such as urbanization, transport, bioenergy, forestry and mining – and so crop production is pushed towards ever more marginal soils.⁴

Yet more worrying is the fierce competition for water, the lifeblood of agriculture. Water withdrawals have increased threefold over the last 50 years, and demand is anticipated to rise by a further 40% by 2030.⁵ With a shift in global production towards intensive systems that rely on groundwater resources for irrigation, along with the current growth in demand for water-intensive animal products, agriculture becomes even thirstier. At the same time, urbanization and industrialization in emerging and developing economies are also driving up demand for fresh water in energy production, mineral extraction, and domestic use, further stretching the already tight supply.⁶

Against this backdrop of tightening constraints, climate change seriously threatens food security in two ways. First, it will harm agricultural production: rising temperatures and changing rainfall patterns will slow yield gains, contributing to higher food prices and an increasingly precarious supply-demand balance that will make markets more prone to volatility. Second, it will increasingly disrupt food systems: more extreme weather will destabilize tighter markets and exacerbate volatility, imperil transport infrastructure and trigger local food crises. As a result, the risks of humanitarian emergencies, national or regional instability and mass migration will increase. In the words of a former Executive Director of the World Food Programme, “without food, people have only three options. They riot, they emigrate, or they die.”⁷ The security implications will be felt by developing and developed countries alike.

In other words, the world might be in trouble on food even if climate change were not a factor. The combination of heat and drought that will be brought on by climate change will add to the risk, potentially destabilizing many populous areas of the world. The world’s response to climate change has been too little, too late, but at least there have been steps in the right direction the last few years. Being willfully ignorant of the risk and reversing the small progress we are making would be an evil, immoral thing to do.