Blog: Dean BestFood security - the debate rages on

Dean Best | 1 April 2014

The IPCC said climate change was already affecting crop yields

The IPCC said climate change was already affecting crop yields

The UN's latest report on climate change grabbed headlines around the world yesterday (31 March) with claims of the "pervasive" impact of global warming, a higher risk of flooding and changes to crop yields. But the report simply refuelled the debate over the precise impact of climate change on food security.

The study from the Intergovernmental Panel on Climate Change (IPCC) led news bulletins here in the UK yesterday, underlining the way environmental issues are now mainstream concerns.

The IPCC sought to detail the impacts of climate change to date, the future risks from a changing climate and the opportunities for effective action to reduce those risks. Over 2,400 experts contributed to the report, which called for action now to help mitigate the consequences of what it called "man-made climate change".

Since the last IPCC report from 2007, climate change is said to present a more direct threat.

"In many cases, we are not prepared for the climate-related risks that we already face. Investments in better preparation can pay dividends both for the present and for the future," Vicente Barros, co-chair of the working group behind the report, said.

Within the food sector, of course, manufacturers and retailers would have thumbed to the section on the impact on crops. The food industry has long believed the issues of climate change and food security are "intrinsically linked".

Concern over commodity prices is high, with a warming world housing an ever-rising population - and a population that, in emerging markets, is increasingly eating more dairy and meat products.

The report stated that for "the major crops" - wheat, rice, and maize - "in tropical and temperate regions, climate change without adaptation is projected to negatively impact production for local temperature increases of 2°C or more above late-20th-century levels".

The IPCC acknowledged "individual locations may benefit". It said: "Projected impacts vary across crops and regions and adaptation scenarios, with about 10% of projections for the period 2030-2049 showing yield gains of more than 10%, and about 10% of projections showing yield losses of more than 25%, compared to the late 20th century."

However, the report added: "Climate change is projected to progressively increase inter-annual variability of crop yields in many regions. These projected impacts will occur in the context of rapidly rising crop demand."

Speaking to the BBC, one of the contributors to the report, Professor Andrew Challinor of the University of Leeds, agreed the impact on crops of a warming planet could be worse than had been previously thought.

"We tried to look at the whole area of food security - not just production but access to food, we looked at fisheries, we looked at crops. Certainly for crops but whether that is true for the whole area of food security is a more difficult question," he said. "We've had indications that we expect year-to-year variations in food production to increase - more of these instances of yields going down due to heatwaves such as happened in Australia and Russia in the last five to ten years. There is emerging evidence of more negative impacts than we had previously thought."

He added: "There is a new environment in which we see food price spikes, rapid increases in prices associated with climate change. That association isn't 1:1 but certainly there is a relationship there."

There was some dissent in academic circles. Professor Richard Tol at the University of Sussex pulled out of the team writing the report, claiming it was "alarmist" about the threats posed by climate change.

Tol told Reuters the report emphasised the risks of climate change more than it did the opportunities for the world to adapt.

He said farmers could grow new crops if the climate became hotter, wetter or drier. "They will adapt. Farmers are not stupid," he told the newswire.

Tol made similar comments in an interview with the BBC. He said the report had not accounted for the recent increases in crop yields from technological advances.

The BBC put Tol's claims of alarmism to Challinor, who replied: "Richard wasn't an author on the food production chapter and I think it is difficult to make broad statements about the data in that way. In the final summary for policymakers, I found the wording to be a little on the conservative side if anything. Within my field, I don't see any evidence of alarmism whatsoever."

On Thursday, just-food will be attending a conference in London on food security. The Westminster Food and Nutrition Forum will hear from Prof. Challinor, as well as representatives from the UK Department for Environment Food and Rural Affairs, the European Commission, the US Department of Agriculture, among others.

It is an opportune time to hear from academics and governments on the issue and we will bring the news and views from the event.

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