Climate Change - Its Impact on Insect Populations & Food Systems

Climate Change - Its Impact on Insect Populations & Food Systems

A recent study conducted by Scott Merrill and his team revealed that rising temperatures could have a negative effect on crops such as Rice, Maize and Wheat especially in temperate regions.The study finds that climate change and increased temperatures could result in increased insect activity leading to losses of millions of tons of food.Global yield losses of these grains are projected to increase by 10 to 25% per degree of global mean surface warming.

By 2050, growing-season temperatures will likely exceed those recorded during the past century and may substantially reduce crop yields. Due to the increasing temperature, insect’s metabolic rate, and rate of food consumption rises accordingly. Crop production losses to pests increase globally with rising temperatures in all climate models and across all biological parameters. With just an increase of 2°C, the median increase in yield losses owing to pest pressure is 46, 19, and 31% for wheat, rice, and maize, respectively, bringing total estimated losses to 59, 92, and 62 metric megatons per year. These losses are proportion to the emissions scenario and on each climate model’s sensitivity to increasing atmospheric CO. The losses will come from an increase in insect metabolism, and from faster insect population growth rates. The link with metabolism is straightforward. Merrill believes that when the temperature increases, the insects' metabolism increases so they have to eat more which is not good for crops. The losses in the temperate regions is greater than those in the tropical regions owing to the fact that temperate regions, warming increases both the size of insect populations and their per capita metabolic rate, while in tropical regions the increasing metabolic rate is offset by declining population growth rates, resulting in a smaller overall rise in crop damages.

The link with population growth, however, is more complex. Insects have an optimal temperature where their population grows best. If the temperature is too cold or too hot, the population will grow more slowly. That is why the losses will be greatest in temperate regions, but less severe in the tropics. "Temperate regions are not at that optimal temperature, so if the temperature increases there, populations will grow faster," said Merrill, an ecologist who studies plant-crop interactions. "But insects in the tropics are already close to their optimal temperature, so the populations will actually grow slower. It's just too hot for them." Wheat, typically grown in cool climates will suffer the largest losses and maize whose cultivation is uneven will face an uneven consequence. France, China and the United States, which produce most of the world's maize, are among the countries that are expected to experience the largest increases in crop losses from insect pests. France and China, as major producers of wheat and rice, respectively, are also expected to face large increases in losses of those grains as well.

Rice, wheat and maize account for 42% of total calories consumed worldwide and with their decline in yields, because so many people around the world rely on them, rise in food security is definite. "There are a lot of things richer countries can do to reduce the effect, by increasing pesticide use or expanding integrated pest management strategies," said Merrill. "But poorer countries that rely on these crops as staple grains will have a harder time." Although the effect of global warming cannot completely be reversed, we can adopt practices that slow down its effects. Non Pesticide Management is one among them. By engaging in the NPM (Non Pesticide Management) agricultural practices, Safe Harvest ensure that the elements of nature are not altered to a point of no return. Refraining from use of synthetic pesticides, following water shed management, encouraging cultivation of sustainable crops like millets are among the few practices we can inculcate on an organizational level. Read more on climate change and its impact on pest populations here: https://science.sciencemag.org/content/361/6405/916?utm_source=Study&utm_medium=All&utm_campaign=InsectClimate Read more about our NPM practices here: https://www.npmnetwork.org/