Tag Archives: Philosophical Transactions of the Royal Society Series A

The end of maize in Africa? A much warmer world calls for completely new ways of farming and consuming

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Philip Thornton, CCAFS/ILRI

A newscaster from Kenya Television Network Local interviews Philip Thornton on the impacts of climate change on the African continent (photo credit: ILRI).

A new publication, Agriculture-Climate Letters, published by the Climate Change, Agriculture and Food Security program, this week highlight a paper published on the impacts of a 4ºC warmer world on African agriculture and food security. The lead author of the paper is Philip Thornton, an agricultural systems analyst with the International Livestock Research Institute (ILRI).

‘. . . The UK Met Office says a 4 degree [warmer] world is quite possible, and will plausibly be reached by 2070 or even 2060–in our children’s lifetimes. This will mean average temperature rises of a massive 15ºC in the Arctic, and 3-8ºC in the world’s most populated areas.

‘. . . Agriculture is highly sensitive even to a 2 degree scenario; a 4 degree world is beyond the bounds of both local and global knowledge, both modern and historical experience. . . .

‘A new paper, Agriculture and food systems in sub-Saharan Africa in a four-plus degree world, by Philip Thornton, Peter Jones, Polly Ericksen and Andrew Challinor, foresees profound effects. . . . [E]nsembles of models suggest average yield drops of 19% for maize and 47% for beans, and much more frequent crop failures. . . . Africa-wide, a massive 1.2 million km2 may be forced to flip from typical mixed farms, with both crops and livestock, into pure rangeland. . . .

‘Thus a 4 degree world calls for adaptive capacity in agriculture that is not just about increasing the resilience of current systems, but about completely new ways of farming and consuming. . . . Thornton and colleagues highlight four areas for immediate policy attention:

  • supporting farmers’ own risk-management strategies
  • strengthening basic data collection in agriculture
  • investing seriously in genebanks
  • improving governance of food systems so that poor people can get affordable food

‘. . . Rapidly urbanising populations will need to eat nationally and regionally grown food. If +4 degrees signals the end to half a millennium of Africans eating maize, will the 21st century usher in a new era of indigenous urban foods, be they free-range hamburgers or drought-resistant yamburgers?

Read the whole article at AgClim Letters: Hamburgers and yamburgers? Four-degree futures for food in Africa, 1 November 2010.

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Read the science paper by Philip Thornton et al. in the British journal Philosophical Transactions of the Royal [Society] Series A: Agriculture and food systems in sub-Saharan Africa in a four-plus degree world, 29 November 2010.

Prognosis for African food security in a 4ºC+ warmer world is bleak–Philip Thornton

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Philip Thornton, CCAFS/ILRI

Kenya Television Network interviews Philip Thornton on the impacts of climate change to the African continent (photo credit: ILRI).

Bottom line implication: A 4-degree warmer world calls for adaptive capacity in agriculture that is not just about increasing the resilience of current systems but about completely new ways of farming and consuming.

The Guardian this week quotes agricultural systems analyst Philip Thornton, of the International Livestock Research Institute (ILRI), on the severe impacts that a 4ºC rise in temperature, now expected to occur within this century, will have on African livelihoods and food production.

'A hellish vision of a world warmed by 4ºC within a lifetime has been set out by an international team of scientists, who say the agonisingly slow progress of the global climate change talks that restart in Mexico today makes the so-called safe limit of 2ºC impossible to keep. A 4ºC rise in the planet's temperature would see severe droughts across the world and millions of migrants seeking refuge as their food supplies collapse.

'"There is now little to no chance of maintaining the rise in global surface temperature at below 2ºC, despite repeated high-level statements to the contrary," said Kevin Anderson, from the University of Manchester, who with colleague Alice Bows contributed research to a special collection of Royal Society journal papers published tomorrow. "Moreover, the impacts associated with 2ºC have been revised upwards so that 2ºC now represents the threshold [of] extremely dangerous climate change.". . .

'Rachel Warren, at the University of East Anglia, described a 4ºC world in her research paper: "Drought and desertification would be widespread. . . . There would be a need to shift agricultural cropping to new areas, impinging on [wild] ecosystems. Large-scale adaptation to sea-level rise would be necessary. Human and natural systems would be subject to increasing levels of agricultural pests and diseases, and increases in the frequency and intensity of extreme weather events."

'Warren added: "This world would also rapidly be losing its ecosystem services, owing to large losses in biodiversity, forests, coastal wetlands, mangroves and saltmarshes [and] an acidified and potentially dysfunctional marine ecosystem. In such a 4ºC world, the limits for human adaptation are likely to be exceeded in many parts of the world.". . .

'In sub-Saharan Africa, "the prognosis for agriculture and food security in a 4ºC world is bleak", according Philip Thornton, of Kenya's International Livestock Research Institute, who led another research team. He notes there will be an extra billion people populating the continent by 2050.

'"Croppers and livestock keepers in sub-Saharan Africa have in the past shown themselves to be highly adaptable to short- and long-term variations in climate. But the kind of changes that would occur in a 4ºC+ world would be way beyond anything experienced in recent times. It is not difficult to envisage a situation where the adaptive capacity and resilience of hundreds of millions of people could simply be overwhelmed by events," Thornton's team concludes. . . .'

Read the whole article at the Guardian: Climate change scientists warn of 4C global temperature rise, 29 November 2010.

‘The limits of human–and natural systems–adaptations are likely to be exceeded’–Climate change researcher Rachel Warren

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A 4-degree C warmer world

Projections of global warming relative to pre-industrial for the A1FI emissions scenario—the one we’re currently on. Dark shading shows the mean ±1 standard deviation for the tunings to 19 AR4 GCMs [IPCC Fourth Assessment General Circulation Models]  and the light shading shows the change in the uncertainty range when . . . climate-carbon-cycle feedbacks . . . are included. Published in a Royal Society special issue on climate change, 29 November 2010 (graphic credit: Philosophical Transactions of the Royal Society Series A, Special Issue, 29 November 2010).

An article in the highly regarded Climate Progress website names a paper by agricultural systems analyst Philip Thornton, of the International Livestock Research Institute (ILRI), titled ‘Agriculture and food systems in sub-Saharan Africa [SSA] in a 4°C+ world’, as one of the more important articles appearing in a current special issue on climate change of the Philosophical Transactions of the Royal Society Series A.

‘”In . . .  a 4°C [warmer] world, the limits for human adaptation are likely to be exceeded in many parts of the world, while the limits for adaptation for natural systems would largely be exceeded throughout the world.”

‘One of the greatest failings of the climate science community (and the media) is not spelling out as clearly as possible the risks we face on our current emissions path, as well as the plausible worst-case scenario, which includes massive ecosystem collapse. So much of what the public and policymakers think is coming is a combination of:

  • The low end of the expected range of warming and impacts based on aggressive policies to reduce emissions (and no serious carbon-cycle feedbacks)
  • Analyses of a few selected impacts, but not an integrated examination of multiple impacts
  • Disinformation pushed by the anti-science, pro-pollution crowd

‘In fairness, a key reason the scientific community hasn’t studied the high emissions scenarios much until recently because they never thought humanity would be so self-destructive as to ignore their warnings for so long, which has put us on the highest emissions path (see U.S. media largely ignores latest warning from climate scientists: “Recent observations confirm … the worst-case IPCC scenario trajectories (or even worse) are being realised”—1000 ppm [A1FI]).

‘A special issue of the Philosophical Transactions of the Royal Society A, “Four degrees and beyond: the potential for a global temperature increase of four degrees and its implications,” lays out this 4°C (7°F) world. Warming of 7ºF is certainly not the worst-case in the scientific literature (see M.I.T. doubles its 2095 warming projection to 10°F—with 866 ppm and Arctic warming of 20°F and “Our hellish future: Definitive NOAA-led report on U.S. climate impacts warns of scorching 9 to 11°F warming over most of inland U.S. by 2090 with Kansas above 90°F some 120 days a year — and that isn’t the worst case, it’s business as usual!”).

‘But for the first time, “A hellish vision of a world warmed by 4ºC within a lifetime has been set out by an international team of scientists,” as the UK’s Guardian describes it:

‘A 4ºC rise in the planet’s temperature would see severe droughts across the world and millions of migrants seeking refuge as their food supplies collapse.

‘These papers began as conference presentations . . . . In a must-read paper that is the source of the top figure, “When could global warming reach 4°C?” Betts et al. drop this bombshell:

‘”Using these GCM projections along with simple climate-model projections, including uncertainties in carbon-cycle feedbacks, and also comparing against other model projections from the IPCC, our best estimate is that the A1FI emissions scenario would lead to a warming of 4°C relative to pre-industrial during the 2070s. If carbon-cycle feedbacks are stronger, which appears less likely but still credible, then 4°C warming could be reached by the early 2060s in projections that are consistent with the IPCC’s ‘likely range’.”. . .

‘Another important Royal Society article is the concluding piece, “The role of interactions in a world implementing adaptation and mitigation solutions to climate change,” by Rachel Warren.  She makes a crucial point that is all too neglected in most discussions of adaptation — it is the interaction of impacts that is likely to overwhelm, particularly when you consider the very real risk of eco-system collapse over large parts of the Earth:

‘”… a 4°C world would be facing enormous adaptation challenges in the agricultural sector, with large areas of cropland becoming unsuitable for cultivation, and declining agricultural yields. This world would also rapidly be losing its ecosystem services, owing to large losses in biodiversity, forests, coastal wetlands, mangroves and saltmarshes, and terrestrial carbon stores, supported by an acidified and potentially dysfunctional marine ecosystem. Drought and desertification would be widespread, with large numbers of people experiencing increased water stress, and others experiencing changes in seasonality of water supply. There would be a need to shift agricultural cropping to new areas, impinging on unmanaged ecosystems and decreasing their resilience; and large-scale adaptation to sea-level rise would be necessary. Human and natural systems would be subject to increasing levels of agricultural pests and diseases, and increases in the frequency and intensity of extreme weather events.

‘”In such a 4°C world, the limits for human adaptation are likely to be exceeded in many parts of the world, while the limits for adaptation for natural systems would largely be exceeded throughout the world. Hence, the ecosystem services upon which human livelihoods depend would not be preserved. Even though some studies have suggested that adaptation in some areas might still be feasible for human systems, such assessments have generally not taken into account lost ecosystem services. . . .

‘. . . [T]here are several important articles, like “Agriculture and food systems in sub-Saharan Africa [SSA] in a 4°C+ world,” which concludes:

‘The prognosis for agriculture and food security in SSA in a 4°C+ world is bleak. Already today, the number of people at risk from hunger has never been higher: it increased from 300 million in 1990 to 700 million in 2007, and it is estimated that it may exceed 1 billion in 2010. The cost of achieving the food security Millennium Development Goal in a +2°C world is around $40–60 billion per year, and without this investment, serious damage from climate change will not be avoided. Currently, the prospects for such levels of sustained investment are not that bright. Croppers and livestock keepers in SSA have in the past shown themselves to be highly adaptable to short- and long-term variations in climate, but the kind of changes that would occur in a 4°C+ world would be way beyond anything experienced in recent times. There are many options that could be effective in helping farmers adapt even to medium levels of warming, given substantial investments in technologies, institution building and infrastructural development, for example, but it is not difficult to envisage a situation where the adaptive capacity and resilience of hundreds of millions of people in SSA could simply be overwhelmed by events. . . .

Read the whole article at Climate Progress: Royal Society special issue details ‘hellish vision’ of 7°F (4°C) world—which we may face in the 2060s!, 20 November 2010.

Scientists warn of farm failures and climate migrants in Africa in a 4-plus degree world

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Maize farming in Mozambique

Smallholder maize and livestock farm in Pacassa Village, in Tete Province, Mozambique (photo credit: ILRI/Mann).

As climate change negotiations begin this week in Mexico, a new study published in the journal Philosophical Transactions of the Royal Society Series A, examining the potential impact of a four-degree temperature increase on food production in sub-Saharan Africa, reports that growing seasons of much of the region’s cropped areas and rangelands will be reduced in length by the 2090s, seriously damaging the ability of these lands to grow food.

Painting a bleak picture of Africa’s food production in a 'four-plus degree world,' the study sends a strong message to climate negotiators at a time when they are trying to reach international consensus on measures needed to keep average global temperatures from rising by more than two degrees Centigrade in this century. The study calls for concerted efforts to help farmers cope with potentially unmanageable impacts of climate change.

In most of southern Africa, growing seasons could be shortened by about 20 per cent, according to the results of simulations carried out using various climate models. Growing seasons may actually expand modestly in eastern Africa. But despite this, for sub-Saharan Africa as a whole, a temperature increase of five degrees by the 2090s is expected to depress maize production by 24 per cent and bean production by over 70 per cent.

'Africa’s rural people have shown a remarkable capacity to adapt to climate variability over the centuries,' said lead author Philip Thornton, with the Kenya-based International Livestock Research Institute (ILRI), which forms part of the Consultative Group on International Agricultural Research (CGIAR). 'But temperature increases of four degrees or more could create unprecedented conditions in dozens of African countries, pushing farmers beyond the limits of their knowledge and experience.' 

It seems unlikely that international climate policies will succeed in confining global warming to a two-degree increase, and even this will require unprecedented political will and collective action, according to the study.

Many options are already available that could help farmers adapt even to medium levels of warming, assuming substantial investment in new technology, institution building, and infrastructure development, for example. But it is quite possible that the adaptive capacity and resilience of hundreds of millions of people in Africa could simply be overwhelmed by events, say the authors.

The rate of cropping season failure will increase in all parts of the region except Central Africa, according to study results. Over a substantial part of eastern Africa, crops already fail in one out of every four years. By the 2090s, higher temperatures will greatly expand the area where crops fail with this frequency. And much of southern Africa’s rainfed agriculture could fail every other season.

'More frequent crop failures could unleash waves of climate migrants in a massive redistribution of hungry people,' said Thornton. 'Without radical shifts in crop and livestock management and agricultural policies, farming in Africa could exceed key physical and socio-economic thresholds where the measures available cease to be adequate for achieving food security or can’t be implemented because of policy failures.'

'This is a grim prospect for a region where agriculture is still a mainstay of the economy, occupying 60 per cent of the work force,' said Carlos Seré, Director General of ILRI. 'Achieving food security and reducing poverty in Africa will require unprecedented efforts, building on 40 years of modest but important successes in improving crop and livestock production.'

To help guide such efforts, the new study takes a hard look at the potential of Africa’s agriculture for adapting successfully to high temperatures in the coming decades; the study also looks at the constraints to doing so.

Buffering the impacts of high temperatures on livestock production will require stronger support for traditional strategies, such as changing species or breeds of animals kept, as well as for novel approaches such as insurance schemes whose payouts are triggered by events like erratic rainfall or high animal death rates, according to the study.

However, Thornton says that uncertainty about the specific impacts of climate change at the local level, and Africa’s weak, poorly resourced rural institutions, hurt African farmers' ability to adopt such practices fast enough to lessen production losses. Moreover, governments may not respond to the policy challenges appropriately, as demonstrated by the 2008 food crisis, when many countries adopted measures like export bans and import tariffs, which actually worsened the plight of poor consumers.

The study recommends four actions to take now to reduce the ways climate change could harm African food security.

1.     In areas where adverse climate change impacts are inevitable, identify appropriate adaptation measures and pro-actively help communities to implement them.

2.     Go 'back to basics' in collecting data and information. Land-based observation and data-collection systems in Africa have been in decline for decades. Yet information on weather, land use, markets, and crop and livestock distributions is critical for responding effectively to climate change. Africa’s data-collection systems could be improved with relatively modest additional effort.

3.     Ramp up efforts to maintain and use global stocks of crop and livestock genetic resources to help Africa’s crop and livestock producers adapt to climate change as well as to the shifts in disease prevalence and severity that such change may bring.

4.     Build on lessons learned in the global food price crisis of 2007–2008 to help address the social, economic and political factors behind food insecurity.

The CGIAR and the Earth System Science Partnership recently embarked on the most comprehensive program developed so far to address both the new threats and new opportunities that global warming is likely to cause agriculture in the world’s developing countries. The Climate Change, Agriculture and Food Security program assembles relevant experts to work with decision makers at all levels—from government ministries to farmers’ fields—to translate knowledge into effective action.

The ILRI study underlines the urgency and importance of that research. It will inform the discussions of some 500 policy makers, farmers, scientists and development experts expected to attend an ‘Agriculture and Rural Development Day’, on 4 December, which will be held alongside a two-week United Nations Conference on Climate Change taking place in Cancún, Mexico. Participants at the one-day event will identify agricultural development options for coping with climate change and work to move this key sector to the forefront of the international climate debate.

'A four-plus degree world will be one of rapidly diminishing options for farmers and other rural people,' said Seré. 'We need to know where the points of no return lie and what measures will be needed to create new options for farmers, who otherwise may be driven beyond their capacity to cope.'

For more information on the program on Climate Change, Agriculture and Food Security, visit www.ccafs.cgiar.org

With no ‘Marshall Plan’ for transiting to a non-carbon economy, we need research to develop ways to adapt to a warmer world

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Setting out to weed a sorghum crop in Niger

A youth sets out with his weeding tool to tend to his family's crop of sorghum in Katanga Village, near Fakara, in Niger (photo credit: ILRI/Mann).

Along with many other major media, Discovery News reported yesterday on a collection of research papers just published that agree that our world is likely to warm by four degrees Centigrade by the end of this century. Among the scientists quoted in these media reports is agricultural systems analyst Philip Thornton, of the International Livestock Research Institute (ILRI), on what the likely impacts will be on agriculture in sub-Saharan Africa. The researchers concur that research to develop new means to adapt to a warmer world are critically needed. Publication of these science papers comes at the start of the United Nations Climate Change Conference being held in Cancún, Mexico.

'Since the late 1990s, many researchers and policy makers have held a two-degree Celsius (3.6-degree Fahrenheit) global temperature increase relative to pre-industrial times as a benchmark limit for global warming, saying that keeping warming below this threshold increases the likelihood that catastrophic changes can be avoided.

'But we are hardly on track to meet that target, researchers say, and an average global warming of four degrees Celsius (7.2 degrees Fahrenheit) by the end of this century is more likely than two.

'In a collection of papers published today in the Philosophical Transactions of the Royal Society A, researchers paint a picture of what a four-degree warmer world might look like, including changes in agriculture and water supply, ecosystems, sea level rise and the displacement of populations.

'"People are talking about two degrees but the chances of actually delivering on that are pretty slim," said Mark New of Oxford University, United Kingdom, one of the researchers who compiled the collection.

'"If we had a kind of a Marshall Plan to transform every major economy to a non-carbon based economy over the next 15 years, it's doable. But that's not going to happen. A lot of work suggests that the most likely outcome is between three and four (degrees increase) with it very likely to be more than four."

'Four degrees would only be a global average. Air over land will warm more than over the oceans, and some places will warm more than others.

'Dry areas are likely to get drier, according to a study of water supply done by New and others, which could have severe implications for agriculture.

'A team led by [Philip] Thornton of the International Livestock Research Institute used models to project the effect of a four-degree temperature increase on crop production in sub-Saharan Africa.

'"The rate of crop failure in southern Africa increases to nearly one in every two years," New said of the study. "You can't continue to rely on your existing crops or practices. There's going to have to be some kind of a transformation."

'"Most of these countries have low capacity to adapt," he added. . . .

'"Some of the impacts could be overcome if society takes adaptive action, but the difference between adapting at two degrees and at four degrees is very different," New said. "There needs to be research into technologies to assist adaptation just as much as we need research into technology for moving out of a carbon based transportation system." . . .'

Read the whole article at Discovery News: The world: Four degrees warmer, 29 November 2010.

Read Philip Thornton’s science paper in Philosophical Transactions of the Royal Society A: Agriculture and food systems in sub-Saharan Africa in a 4 ° C + world, 29 November 2010.