Climate Change is Reducing Crop Yields When We Need to Produce More Food

By Alison Withers

Scientists in the USA have found that global warming is having an adverse effect on crop yields and is reducing them significantly in some countries.

The study, published in the journal Science, looked at how rising temperatures were affecting annual crop yields in major producer nations over a 12 year period up to 2008.

They used computer models to assess how much grain would have been harvested in the absence of warming and taking into account that yields have been rising overall in the period. The discovered that global wheat production was 33m tonnes (5.5%) below the level at which it would have been without warming and maize production was 23m tonnes (3.8%) lower.

While some countries also experienced lower production of rice and soybeans these drops were balanced by gains in other countries. The scientists calculated that the reduction in yield could potentially have pushed up food prices by as much as 18.9%.

They argue that their findings demonstrate the importance of finding ways to adapt farming to a warmer world if we want to make sure that rises in global population are matched by rising food production.

While climate change is one factor to be considered in trying to match food production to a growing population there are others, which include the switch to crop production for biofuels, growth in the demand for meat, and therefore for animal fodder, and the degree of commodity price speculation that has been happening recently.

Plainly the pressure on farmers in dealing with all these issues is intense and it is perhaps not helped by another recent piece of research that found that consumers are woefully ignorant about food and where it comes from. It included such wild misconceptions as 26% thought bacon came from sheep, 29% believed oats grew on trees and 17% thought eggs were an ingredient of bread.

A new initiative from the UK's National Trust is designed to help with that. They have devised an online initiative called MyFarm, based on a real farm, which will involve up to 10,000 people helping to make decisions on what to do.

Every month the farm manager will put a policy question on crops, livestock or wider impacts, summarising the implications of the options open to him in terms of profitability, management, the environment and so on. The signed-up members will then vote on what he should do.

One thing it could help to raise awareness of is the way unit costs mount when yields are low. It remains to be seen whether it will get into the detail of choosing between such things as different types of pesticides and fertilisers for crop protection and improving yield.

For example, choosing the right combination of conventional and the new ranges of low-chem agricultural products, including biopesticidesand biofungicides, both derived from naturally-occurring sources, has been shown to improve crop yields and help in farming productively and sustainably.

It will be interesting to watch the MyFarm experiment and whether it eventually gets into this sort of detail and improves consumer understanding of the food production process.

Alison Withers
Article by Alison Withers
It is likely that farming and farming methods will need to change in response to results of research showing that crop yields for wheat, rice, soya and maize, have dropped as global warming has increased in the last decade. Can the new generation biopesticides, biofungicides and yield enhancers help?

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