Here is the power point presentation in French (Séminaire Œuvre Durable)
According to Stanford research U.S. corn yields are growing more sensitive to heat and drought. Farmers are faced with difficult tradeoffs in adapting to a changing climate in which unfavorable weather will become more common.
The study, which appears in the journal Science, was led by Stanford’s David Lobell, associate professor of environmental Earth system science and associate director of the Center on Food Security and the Environment. “The Corn Belt is phenomenally productive,” Lobell said, referring to the region of Midwestern states where much of the country’s corn is grown. “But in the past two decades we saw very small yield gains in non-irrigated corn under the hottest conditions. This suggests farmers may be pushing the limits of what’s possible under these conditions.”
He predicted that at current levels of temperature sensitivity, crops could lose 15 percent of their yield within 50 years, or as much as 30 percent if crops continue the trend of becoming more sensitive over time.
As Lobell explained, the quest to maximize crop yields has been a driving force behind agricultural research as the world’s population grows and climate change puts pressure on global food production. One big challenge for climate science is whether crops can adapt to climate change by becoming less sensitive to hotter and drier weather.
“The data clearly indicate that drought stress for corn and soy comes partly from low rain, but even more so from hot and dry air. Plants have to trade water to get carbon from the air to grow, and the terms of that trade become much less favorable when it’s hot,” said Lobell, also the lead author for a chapter in the U.N. Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, which details a consensus view on the current state and fate of the world’s climate.
Rain, temperature, humidity
The United States produces 40 percent of the world’s corn, mostly in Iowa, Illinois, and Indiana. As more than 80 percent of U.S. agricultural land relies on natural rainfall rather than irrigation, corn farmers in these regions depend on precipitation, air temperature and humidity for optimal plant growth.
According to the research, over the last few decades, corn in the United States has been modified with new traits, like more effective roots that better access water and built-in pest resistance to protect against soil insects. These traits allow farmers to plant seeds closer together in a field, and have helped farmers steadily raise yields in typical years.
But in drought conditions, densely planted corn can suffer higher stress and produce lower yields. In contrast, soybeans have not been planted more densely in recent decades and show no signs of increased sensitivity to drought, the report noted.
Drought conditions are expected to become even more challenging as temperatures continue to rise throughout the 21st century, the researchers said.
Lobell said, “Recent yield progress is overall a good news story. But because farm yields are improving fastest in favorable weather, the stakes for having such weather are rising. In other words, the negative impacts of hot and dry weather are rising at the same time that climate change is expected to bring more such weather.”
Lobell’s team examined an unprecedented amount of detailed field data from more than 1 million USDA crop insurance records between 1995 and 2012.
“The idea was pretty simple,” he said. “We determined which conditions really matter for corn and soy yields, and then tracked how farmers were doing at different levels of these conditions over time. But to do that well, you really need a lot of data, and this dataset was a beauty.”
Lobell said he hopes that the research can help inform researchers and policymakers so they can make better decisions.
“I think it’s exciting that data like this now exist to see what’s actually happening in fields. By taking advantage of this data, we can learn a lot fairly quickly,” he said. “Of course, our hope is to improve the situation. But these results challenge the idea that U.S. agriculture will just easily adapt to climate changes because we invest a lot and are really high-tech.”
Lobell and colleagues are also looking at ways crops may perform better under increasingly hot conditions. “But I wouldn’t expect any miracles,” he said. “It will take targeted efforts, and even then gains could be modest. There’s only so much a plant can do when it is hot and dry.”
Laura Seaman is the communications and external relations manager for Stanford’s Center on Food Security and the Environment, a joint program of Stanford’s Freeman Spogli Institute for International Studies and the Stanford Woods Institute for the Environment.
Overcoming the threats to agriculture and food security in a changing climate requires a strong scientific evidence base to both help smallholder farmers choose resilient strategies and to guide development policy and investments.
Building on a Bioversity and CCAFS systematic review of the role of diversification in agricultural systems, the Platform for Agrobiodiversity Research is now hosting the ReFARM (the Resilience Framework for Agriculture and Risk Management) Database, to feature hundreds of reviewed case studies on these issues.
Case studies can be quickly screened according to a range of categories including region, scale, climate risks, diversification type and other management categories, along with other features of agricultural systems. Practitioners who would like to contribute their own work are invited to submit a case directly through the site.
So far the database has 37 case studies on diversification and livestock …
Follow the link to the web site ReFARM
by Courtney White, originally published by The carbon pilgrim | Mar 29, 2013
This is a blog about carbon, and by extension climate change mitigation, but there’s another big job that’s rising fast on a lot of people’s To Do lists. It’s called adaptation, and suddenly everyone’s talking about it – for good reason as I learned last week. And the reason is this: the future is now. Climate-related changes are bearing down on us faster than many scientists expected, requiring action by individuals, communities, cities, and nations to reduce their effects. Inaction (like so much else connected to climate change) will only magnify the challenges, making them much harder to solve later.
In other words, our collective To Do list just got a lot longer.
Before I explain what I learned, however, I want to back up for a moment and review the overall troika of action required by climate change: (1) Reduction of greenhouse gas emissions on a global scale; (2) Mitigation of atmospheric greenhouse gases through strategies that capture and store them long-term; and (3) Adaptation to ongoing effects of climate change as well as planning for new or increased effects in the future. Of the three, reducing emissions is by far and away the most critical. If the arrow of greenhouse gas production doesn’t turn downward, then we’re ultimately spitting into a hot, dry wind. However, as a result of decades of inaction by polluting nations, the other two strategies are rising in necessity as well. We need mitigation in order to soak up as much excess pollution as possible, as I’ve tried to describe here, but we need to adapt to changing conditions too – and quickly. Look at what hit the U.S. in 2012, for example, or Australia’s just concluded record-breaking heat and floods, dubbed the Angry Summer by the government. As I said, the future is now.
Just how now hit home over the course of three days in Hamburg, Germany, last week when I attended the European Climate Change Adaptation Conference. I and 700 others, mostly researchers, heard report after report about how the social and environmental stresses caused by climate change are bearing down across the globe right now. We also heard about the significant planning and other actions taking place in response to these stresses. In fact, I was very impressed by all the work going on worldwide.
The conference was dominated by scientific research on adaptation, and many of the 20-minute papers were delivered by professors or grad students, but there were a number of non-academic perspectives as well, including some from nonprofit organizations. It was clear that the various challenges posed by adaptation are complex, costly, and pressing. And it’s way too early to know if any particular effort will be sufficient in the long run (much depends on the reduction of greenhouse gases). But one thing was clear: this topic is rising fast.
I learned that all nations in European Union have created, or are creating, national Adaptation Strategy plans and on April 29th, the European Union itself will release its long-awaited continent-wide Adaptation Strategy, which will drive many policy decisions and most of the funding connected to climate change planning among EU members.
What the planners said they need most from researchers is what they called “fit-for-purpose” data, meaning they need to know about risk, vulnerabilities, and possible scenarios as localized as possible so they can ‘fit’ it to their needs. There was a general lament that this information is not available yet in sufficient amounts for city leaders, policy makers and others to make firm plans about adaptation. Models are fine, they said, but we need to know about the real risks. This is a huge need and it is driving much of the research work underway right now. Flood planning, for example, due to rising sea levels and intensifying storms is a major area of research.
The #1 job of adaptation research, I learned, is to reduce uncertainty – i.e., what are the range of impacts to be expected? What exposures and disruptions might we expect? And perhaps most importantly, what adaptation means under rising global temperature scenarios: 2 degrees Celsius? 3 C? 4 C? 5 C? What do these numbers mean for heat, precipitation, floods, etc?
This issue struck home in a graphic provided by Michael Morecroft, of Natural England, in his talk. It showed an arrow, running left to right, through a list of global temperatures: 1 C, 2 C, 3C, 4 C, 5 C. Beneath the 1 C and 2 C part of the arrow was the word Resilience. Below 3 C and 4 C was the word Accommodation. And below the 4 C and 5 C part of the arrow was the word Transformation. His point was this: we can do resilience until temps reach 2 C – meaning we can try to ‘bounce back’ to conditions that we consider relatively normal. After 2 C, however, we must accommodate ourselves to a changing world. After 4 C, the world will be transformed into something else altogether.
His point is that adaptation right now is largely about maintaining the resilience of a system. The planet has warmed a little less than 1 C to date, with another 1 C on the way. Adaptation planning, he said, should focus on this 1-2 C scenario while we redouble our efforts to reduce greenhouse gas emissions. Beyond 2 C, however, adaptation means something else. What that is exactly, scientists don’t know yet, he said. He also said that mitigation takes longer than people expect, research is showing. That’s why an emphasis on adaptation in the short run is so important.
Here’s a PDF of a paper by Morecroft et al on this topic: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2664.2012.02136.x/pdf
As an illustration, here’s a photo of heat in Australia recently:
I learned also that case studies are critically important to planners. It helps them understand the issue of adaptation in real terms. Copenhagen, for example, has embarked on an ambitious plan to become a major “Blue-Green city” down to the household level, including ideas like placing washing machines on top of toilets to recycle water.
Here are a few others that I heard:
- Dislocation (Taiwan). Climate change is predicted to dislocate large numbers of people, including whole villages. Challenges include: no legal authority; few precedents; insufficient funding; unanticipated consequences; unrealistic expectations; no guidelines; lots of disagreement; underestimated costs; social and economic stress; social justice questions; and what if villagers refuse to move? On the other hand, disruption could be balanced by innovation as creative minds work together to solve problems.
- Australia’s Angry Summer. 123 records were broken in 90 days (heat & floods); incidents of domestic violence and homelessness spiked; charismatic leadership made a big difference in the quality of the adaptive response and the degree to which suffering was reduced; new funding sources are required for this type of emergency; it brought home the critical need to move from emergency response to long-term adaptation planning; at the same time, ‘climate fatigue’ is settling in, Australians are getting tired of hearing about climate change all the time and wish the topic would just “go away.”
- The Role of New Technology (Austria). Researchers are trying to determine what types of technology can help cities adapt to climate change (software and hardware). Is it more useful to look at high tech, or low tech solutions?
- Flooding and Erosion (Nigeria). Intense storms are causing gullying and other types of severe erosion in villages and fields in rural Nigeria. The photos were amazing. The speaker advocated for a return to ‘traditional knowledge’ practices in response to this situation.
- Adjusting Agricultural Practices (Ecuador). Farmers in a highland village are seeing climate change affect them via higher temperatures, more extreme weather, increased seasonal variability; and prolonged drought, all of which expose vulnerabilities. Effects include: increased (and new) pest attacks, water scarcity, heat stress on plants and farmers, increased erosion, deteriorating fieldwork conditions, seed storage loss, rot, plant dessication, and poor animal performance. Solutions include: increased use of pesticides, earlier harvest dates, development of new water sources, buying seeds from corporations, moving farm fields to higher elevations, planting more drought-tolerant plant species, moving planting dates.
- Coastal Defense (Germany). The term “coastal defense” has a very different meaning today under climate change than it did in the past. Hamburg in particular is worried about sea level rise and flooding from storms. It is the second busiest port in the world, after Shaghai, and it is actively engaged in climate change adaptation planning in this regard.
Finally, there was a great deal of discussion during the conference on how to put research into practice. It was one thing to create ‘models of vulnerability,’ as many scientists have done, and quite another to translate them into plans of action. People want (and need) to make informed decisions, especially since adaptation can be so expensive to do, but getting useful information into the hands of implementers and regular folk has been slow to date. Local governments are on the front lines, but they often don’t know what to do. Scientists can help by making a range of options available to local leaders, who then have to sell the options to a reluctant and skeptical citizenry. It’s a difficult but urgent task.
As one speaker put it: “People want to live normal lives, they don’t feel responsible for the problem, they’ve not been well led, and they’re generally ignorant of the seriousness of the problem that’s approaching. Research can help will all of these areas.”
But time is getting short. The effects of climate change are happening faster than anyone really expected. One conference organizer said: “This conference would not have happened even five years ago.” The urgency is real, but so are the efforts of a great deal of people. Clearly, a lot of important work is underway and I was impressed by the seriousness and dedication of all the speakers.
Here’s a photo of an Ecuador farmer (courtesy of National Geographic):