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Half of world’s population could face climate-driven food crisis in second half of the century
Submitted by Norm Roulet on Thu, 02/24/2011 - 14:09.
From Climate Progress:
Yes, this 2009 study is a serious underestimate of the speed and scale of likely impacts for two reasons.
First, the conclusions are solely based upon projected temperature rise. They don’t even consider the potentially more devastating impact from more extreme drought and Dust-Bowlification (See NCAR analysis warns we risk multiple, devastating global droughts by mid-century even on moderate emissions path) — let alone the combination of heat stress and water stress together.
Second, as is common in such analyses, the authors based their simulations on “the ‘middle of the road’ emission scenario, A1B.” In 2100, A1B hits about 700 ppm with average global temperatures “only” about 3°C (5 F) warmer than today. In fact, on our current emissions path, a 3C temperature rise will happen much sooner (see Hadley Center: “Catastrophic” 5-7°C warming by 2100 on current emissions path and M.I.T. doubles its 2095 warming projection to 10°F — with 866 ppm and Arctic warming of 20°F). And remember, the worst-case scenario is that this happens by mid-century (se Royal Society special issue details ‘hellish vision’ of 7°F (4°C) world — which we may face in the 2060s!)
Figure. “Histogram of summer (June, July, and August) averaged temperatures (blue) observed from 1900 to 2006 and (red) projected for 2090 for (A) France, (B) Ukraine, and (C) the Sahel. Temperature is plotted as the departure from the long-term (1900–2006) climatological mean (21). The data are normalized to represent 100 seasons in each histogram. In (A), for example, the hottest summer on record in France (2003) is 3.6°C above the long-term climatology. The average summer temperature in 2090 [assuming A1B] is projected to be 3.7°C greater than the long-term climatological average.”
The results are still alarming:
If the authors had modeled the Hadley or M.I.T. or other current business-as-usual scenarios, then I suspect even in the temperate regions, growing season temperatures in 2100 would exceed the most extreme temperatures recorded in the past century — while the tropics and subtropics will be utterly brutalized.
Indeed, along with the temperature rise, we face desertification of one third the habited planet and moderate drought over half the land mass. Soil moisture drops over large parts of the planet will exceed that of the 1930s Dust Bowl! And lasting a long, long time (see NOAA: Climate change “largely irreversible for 1000 years,” with permanent Dust Bowls in Southwest and around the globe).
The study warns that the rich countries will also suffer:
Yet, by century’s end, the European summer of 2003 will be considered relatively cool. What do the authors recommend?
Rather lamely, the study never mentions the possibility of mitigation, of keeping total global warming to far less than 3°C, as a strategy. Why? The final paragraph of the release states:
Okay. Fine. Another understatement of the year.
But since the authors clearly assert in the study that we’re also not doing a very good job of adaptation or investment in agriculture, I’m not sure why it makes more sense for them to push adaptation as a solution than mitigation. In fact, we’ll need to do both, but absent serious mitigation, “climate adaptation” may be little more than cruel doubletalk for most of the world [see Real adaptation is as politically tough as real mitigation, but much more expensive and not as effective in reducing future misery; Rhetorical adaptation, however, is a political winner. Too bad it means preventable suffering for billions].
[Note to authors -- if you ignore mitigation, than you need to model an emissions scenarios that does not have much if any mitigation. Try A1F1 next time.]
If we end up with 5.5°C warming or more by century’s end, and if you throw in the desertification and sharps drops in soil moisture — plus the loss of the inland glaciers that act as reservoirs for so many major river systems around the globe — then simply developing crops “that are tolerant to heat and heat-induced water stress” along with better irrigation is likely to prove utterly inadequate and irrelevant for billions of people.
And let’s not forget where we’re ultimately heading — Science stunner: On our current emissions path, CO2 levels in 2100 will hit levels last seen when the Earth was 29°F (16°C) hotter
The only genuine hope for avoiding “the worst form of triage” is aggressive and immediate greenhouse gas mitigation.
For more, see the posts under the category “food insecurity.”