Climate could devastate crops

[cedric]

http://news.bbc.co.uk/1/hi/sci/tech/7220807.stm

Climate 'could devastate crops'

The work can help prioritise investment, say the authors
Climate change could cause severe crop losses in South Asia and southern Africa over the next twenty years, a study in the journal Science says.
The findings suggest southern Africa could lose more than 30% of its main crop, maize, by 2030.

In South Asia losses of many regional staples, such as rice, millet and maize could top 10%, the report says.

The effects in these two regions could be catastrophic without effective measures to adapt to climate change.

The majority of the world's one billion poor depend on agriculture for their livelihoods. Yet, said lead author David Lobell, it is also "the human enterprise most vulnerable to climate change".

The researcher, from Stanford University in California, added: "Understanding where these climate threats will be greatest, for what crops and on what time scales, will be central to our efforts at fighting hunger and poverty over the coming decades."

'Crushing' losses

The study used computer models to assess the impact of climate change on farming in 12 world regions where the bulk of the world's malnourished people live. This included much of Asia, sub-Saharan Africa, the Caribbean and Central and South America.

"To identify which crops in which regions are most under threat by 2030, we combined projections of climate change with data on what poor people eat, as well as past relationships between crop harvests and climate variability," Dr Lobell explained.

The scale and speed of the effects on agriculture surprised the scientists.

"For poor farmers on the margin of survival, these losses could really be crushing," said co-author Marshall Burke, also of Stanford University.

All the models agree that there will be adverse effects on maize in southern Africa and rice in South-East Asia, but the picture is less certain in other areas such as parts of West Africa where it is unclear how global warming will impact the local climate.

Early investment

"For these regions, you get half of the climate models telling you it's going to get wetter and the other half giving you the opposite," said Dr Burke.

"As a result, our study raises the potential for very bad impacts in these regions but with much less certainty than in other regions."

A few developing regions, such as the temperate wheat-growing areas of China, could actually benefit in the short run from climate change, he added.

Since it typically takes 15 to 30 years for major agricultural investments to be fully realised, work must start soon to help subsistence farmers increase their yields or switch crops, the study says.

While relatively inexpensive changes, such as switching crops or altering planting seasons, could trim the losses, "the biggest benefits will likely result from more costly measures, including the development of new crop varieties and expansion of irrigation," the authors wrote.

[GliderGuider]

1. Lets put this in a broader perspective for Africa

Here's a look at other events that will influence Africa's food situation over the next 25 years:

• Africa today imports 25% of its food calories.
  
• An overall loss of 25% of their grain production would raise their import level to over 40%.
  
• The African population is going to expand by 50% by 2030 (it's projected to double by 2050).
  
• That would raise their calorie import requirement to 65% of total consumption, or almost 4 times today's requirement.
  But then:
  
• As energy supplies decline world-wide, according to my analysis total African GDP will decline, perhaps by as much as 25% by 2030. With the rise in population, per capita incomes could drop by 40%.
  
• Peak Gas means that world fertilizer prices will probably quadruple by then (after all, they've doubled in the last 5 years, in constant dollars).
  
• The inability of African farmers with reduced incomes to buy fertilizer could cut crop yields another 20% or so.
  
• That reduction would raise the food import requirement in 2030 to 5 times what it is today.

Africa's food import costs went from $2 billion in 1970 to $12.5 billion in 1985. That means they are probably around $20 billion today. If the above projections are realistic, their food import costs will jump to the neighborhood of $100 billion by 2030. That would require spending 10% of Africa's total GDP on food imports.

It's somewhat worse than that, though, because the cost of grain on the world market is rising even now due to crop failures, meat production and competition from agrifuels. If food prices go up by 50% in constant dollars by 2030, Africa will be spending 15% of its total GDP on imported food.

Of course aggregated figures like this say nothing about the distribution of misery among different countries. Some will do a little better than this, some will do a lot worse.

By 2030 Africa will probably be in the grip of the worst human catastrophe the world has ever seen.

By the way cedric, welcome to DU and E/E! :hi:

[cedric]

2. Thanks

Interesting site

[kestrel91316]

3. Really?? WOW.

:wow:

No one could have forseen THIS.