The Right And The Climate
Climate change legislation has been dying in the Senate for months now, but Harry Reid’s decision to finally admit as much — in the midst of an endless East Coast heat wave, no less — has supporters of cap-and-trade casting about for somebody to blame. They’ve blamed the Obama administration, for prioritizing health care reform over an energy bill. They’ve blamed the American people, for being too concerned with economic issues to grapple with longer-term threats. And they’ve blamed figures like Lindsey Graham and John McCain, erstwhile supporters of cap-and-trade who have steadily backpedaled away from it.
But most of all, they’ve blamed conservatives — for pressuring Republican lawmakers to abandon legislation they once supported, and for closing ranks against any attempt to tax and regulate our way to a lower-carbon economy. Read more
Scientific Expertise Lacking Among ‘Doubters’ Of Climate Change
The small number of scientists who are unconvinced that human beings have contributed significantly to climate change have far less expertise and prominence in climate research compared with scientists who are convinced, according to a study led by Stanford researchers.
In a quantitative assessment – the first of its kind to address this issue – the team analyzed the number of research papers published by more than 900 climate researchers and the number of times their work was cited by other scientists.
“These are standard academic metrics used when universities are making hiring or tenure decisions,” said William Anderegg, lead author of a paper published in the online Early Edition of Proceedings of the National Academy of Sciences this week.
Expertise was evaluated by the number of papers on climate research written by each individual, with a minimum of 20 required to be included in the analysis. Climate researchers who are convinced of human-caused climate change had on average about twice as many publications as the unconvinced, said Anderegg, a doctoral candidate in biology. Read more
Climate Change Likely To Complicate Plant Diseases Of The Future
Climate change is expected to create yet another problem – complications in plant diseases of the future.
University of Illinois researchers are studying the impact of elevated carbon dioxide, elevated ozone and higher atmospheric temperatures on plant diseases that could challenge crops in these changing conditions.
“Plants growing in a high carbon dioxide environment tend to grow faster and larger, and they have denser canopies,” said Darin Eastburn, U of I associate professor of crop sciences.
“These dense plant canopies favour the development of some diseases because the low light levels and reduced air circulation allow higher relative humidity levels to develop, and this promotes the growth and sporulation of many plant pathogens.”
At the same time, plants grown in high carbon dioxide environments also close their stomata, pores in the leaves that allow the plant to take in carbon dioxide and release oxygen, more often. Read more
CO2 Effects On Plants Increases Global Warming
Trees and other plants help keep the planet cool, but rising levels of carbon dioxide in the atmosphere are turning down this global air conditioner. According to a new study by researchers at the Carnegie Institution for Science, in some regions more than a quarter of the warming from increased carbon dioxide is due to its direct impact on vegetation. This warming is in addition to carbon dioxide’s better-known effect as a heat-trapping greenhouse gas. For scientists trying to predict global climate change in the coming century, the study underscores the importance of including plants in their climate models.
“Plants have a very complex and diverse influence on the climate system,” says study co-author Ken Caldeira of Carnegie’s Department of Global Ecology. “Plants take carbon dioxide out of the atmosphere, but they also have other effects, such as changing the amount of evaporation from the land surface. It’s impossible to make good climate predictions without taking all of these factors into account.”
Plants give off water through tiny pores in their leaves, a process called evapotranspiration that cools the plant, just as perspiration cools our bodies. On a hot day, a tree can release tens of gallons of water into the air, acting as a natural air conditioner for its surroundings. The plants absorb carbon dioxide for photosynthesis through the same pores (called stomata). But when carbon dioxide levels are high, the leaf pores shrink. This causes less water to be released, diminishing the tree’s cooling power.
The warming effects of carbon dioxide as a greenhouse gas have been known for a long time, says Caldeira. But he and fellow Carnegie scientist Long Cao were concerned that it is not as widely recognized that carbon dioxide also warms our planet by its direct effects on plants. Previous work by Carnegie’s Chris Field and Joe Berry had indicated that the effects were important. “There is no longer any doubt that carbon dioxide decreases evaporative cooling by plants and that this decreased cooling adds to global warming,” says Cao. “This effect would cause significant warming even if carbon dioxide were not a greenhouse gas.”
In their model, the researchers doubled the concentration of atmospheric carbon dioxide and recorded the magnitude and geographic pattern of warming from different factors. They found that, averaged over the entire globe, the evapotranspiration effects of plants account for 16% of warming of the land surface, with greenhouse effects accounting for the rest. But in some regions, such as parts of North America and eastern Asia, it can be more than 25% of the total warming. “If we think of a doubling of carbon dioxide as causing about four degrees of warming, in many places three of those degrees are coming from the effect of carbon dioxide in the atmosphere, and one is coming from the direct effect of carbon dioxide on plants.”
The researchers also found that their model predicted that high carbon dioxide will increase the runoff from the land surface in most areas, because more water from precipitation bypasses the plant cooling system and flows directly to rivers and streams. Earlier models based on greenhouse effects of carbon dioxide had also predicted higher runoff, but the new research predicts that changes in evapotranspiration due to high carbon dioxide could have an even stronger impact on water resources than those models predict.
“These results really show that how plants respond to carbon dioxide is very important for making good climate predictions,” says Caldeira. “So if we want to improve climate predictions, we need to improve the representation of land plants in the climate models. More broadly, it shows that the kind of vegetation that’s on the surface of our planet and what that vegetation is doing is very important in determining our climate. We need to take great care in considering what kind of changes we make to forests and other ecosystems, because they are likely to have important climate consequences.”
The study is published in the May 3-7 online edition of the Proceedings of the National Academy of Sciences. redOrbit
Global Warming May Hurt Some Poor Populations
The impact of global warming on food prices and hunger could be large over the next 20 years, according to a new Stanford University study. Researchers say that higher temperatures could significantly reduce yields of wheat, rice and maize – dietary staples for tens of millions of poor people who subsist on less than $1 a day. The resulting crop shortages would likely cause food prices to rise and drive many into poverty.
But even as some people are hurt, others would be helped out of poverty, says Stanford agricultural scientist David Lobell.
“Poverty impacts depend not only on food prices but also on the earnings of the poor,” said Lobell, a center fellow at Stanford’s Program on Food Security and the Environment (FSE). “Most projections assume that if prices go up, the amount of poverty in the world also will go up, because poor people spend a lot of their money on food. But poor people are pretty diverse. There are those who farm their own land and would actually benefit from higher crop prices, and there are rural wage laborers and people that live in cities who definitely will be hurt.”
Lobell and his colleagues recently conducted the first in-depth study showing how different climate change scenarios could affect incomes of farmers and laborers in developing countries. He presented the results on Feb. 20 at the annual meeting of the American Association for the Advancement of Science in San Diego.
Household incomes
In the study, Lobell, former FSE researcher Marshall Burke and Purdue University agricultural economist Thomas Hertel focused on 15 developing countries in Asia, Africa and Latin America. Hertel has developed a global trade model that closely tracks the consumption and production of rice, wheat and maize on a country-by-country basis. The model was used to project the effects of climate change on agriculture within 20 years and the resulting impact on prices and poverty.
Using a range of global warming forecasts, the researchers were able to project three different crop-yield scenarios by 2030:
* “Low-yield” – crop production is toward the low end of expectations.
* “Most likely” – projected yields are consistent with expectations.
* “High-yield” – production is higher than expected.
“One of the limitations of previous forecasts is that they don’t consider the full range of uncertainties – that is, the chance that things could be better or worse than we expect,” Lobell said. “We provided Tom those three scenarios of what climate change could mean for agricultural productivity. Then he used the trade model to project how each scenario would affect prices and poverty over the next 20 years.
“The impacts we’re talking about are mainly driven by warmer temperatures, which dry up the soil, speed up crop development and shut down biological processes, like photosynthesis, that plants rely on,” he added. “Plants in general don’t like it hotter, and in many climate forecasts, the temperatures projected for 2030 would be outside the range that crops prefer.”
Results
The study revealed a surprising mix of winners and losers depending on the projected global temperature. The “most likely” scenario projected by the International Panel on Climate Change is that global temperatures will rise 1.8 degrees Fahrenheit (1 degree Celsius) by 2030. In that scenario, the trade model projected relatively little change in crop yields, food prices and poverty rates.
But under the “low-yield” scenario, in which temperatures increase by 2.7 F (1.5 C), the model projects a 10 to 20 percent drop in agricultural productivity, which results in a 10 to 60 percent rise in the price of rice, wheat and maize. Because of these higher prices, the overall poverty rate in the 15 countries surveyed was expected to rise by 3 percent.
However, an analysis of individual countries revealed a far more complicated picture. In 11 of the 15 countries, poor people who owned their own land and raised their own crops actually benefitted from higher food prices, according to the model. In Thailand, for example, the poverty rate for people in the non-agricultural sector was projected to rise 5 percent, while the rate for self-employed farmers dropped more than 30 percent – in part because, as food supplies dwindled, the global demand for higher-priced crops increased.
“If prices go up and you’re tied to international markets, you could be lifted out of poverty quite considerably,” Lobell explained. “But there are a lot of countries, like Bangladesh, where poor people are either in urban areas or in rural areas but don’t own their own land. Countries like that could be hurt quite a lot. Then there are semi-arid countries – like Zambia, Mozambique and Malawi – where even if prices go up and people own land, productivity will go down so much that it can’t make up for those price increases. In the ‘low-yield’ scenario, those countries would see higher poverty rates across all sectors.”
Under the “high-yield” scenario, in which global temperatures rise just 0.9 F (0.5 C), crop productivity increased. The resulting food surplus led to a 16 percent drop in prices, which could be detrimental to farm owners. In Thailand, the poverty rate among self-employed farmers was projected to rise 60 percent, while those in the non-agriculture sector saw a slight drop in poverty. In Zambia, Mozambique, Malawi and Uganda, poverty in the non-farming sector was projected to decline as much as 5 percent.
Risk management
Lobell said that, although the likelihood of the “low-yield” or “high-yield” scenario occurring is only 5 percent, it is important for policymakers to consider the full range of possibilities if they want to help countries adapt to climate change and ultimately prevent an increase in poverty and hunger.
“It’s like any sort of risk management or insurance program,” he said. “You have to have some idea of the probability of events that have a big consequence. It’s also important to keep in mind that any change, no matter how extreme, will benefit some households and hurt others.”
The Program on Food Security and the Environment at Stanford is an interdisciplinary research and teaching program that generates policy solutions to the persistent problems of global hunger and environmental damage from agricultural practices worldwide. The program is jointly run by Stanford’s Woods Institute for the Environment and the Freeman Spogli Institute for International Studies. redOrbit