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Scientists say climbing mercury will decrease crop yields

Food crisis looms for growing population. Is drought and heat the “new norm,” for U.S. agriculture? What is driving global weather changes?

Predictions of another potentially hot and dry growing season across large areas of the nation has many wondering if the previous two years of extreme heat and drought experienced in the U.S. is the “new norm,” and if so, what is driving global weather changes in modern times?

A new European study may shed light on that question and may provide hope if world leaders are willing to accept that Earth’s environment is indeed changing. The study indicates a global food crisis could be delayed by years if carbon emissions are reduced worldwide, but warns that extreme and record-breaking heat waves like those experienced last year across Europe and in 2003 could become more frequent if greenhouse gas emissions continue to affect the climate.

The study, jointly conducted by UK’s University of Leeds and the University of Reading, and first published in The Guardian, cites severe heat waves, such as those currently seen in Australia, as potential threats to the world food supply by reversing a trend for rising crop yields and because such extreme weather conditions like last year’s flooding in the UK will become more frequent in the years ahead.

The study further claims extreme heat last year in North America lead to 2012 being the hottest year on record in the United States and the worst crop year in more than two decades. The new research, which cited corn test sites in France, predicts possible crop losses of up to 12 percent for corn over the next two decades and suggests wheat and soybean production could fall by as much as 30 percent by 2050 as the world continues to warm.

Global warming controversy

The issues of global warming and climate change have long been a source of controversy in political circles, but in a U.S. Environmental Protection Agency 2012 Updated Report, scientists conclude that Earth's climate is indeed changing. Temperatures are rising, snow and rainfall patterns are shifting, and more extreme climate events –like heavy rainstorms and record high temperatures—are already affecting society and ecosystems. The report indicates scientists are now confident that many of the observed changes in the climate can be linked to the increase in greenhouse gases in the atmosphere, caused largely by people burning fossil fuels to generate electricity, to heat and cool buildings, and to power vehicles.

An independent study conducted by the University of Lisbon predicts 'mega-heat waves' like the one estimated to have killed tens of thousands in Western Europe in 2003 will become up to 10 times more likely over the next 40 years. The study further reveals that the Eastern European heat wave of 2010 blamed for the deaths of many people and for devastated crops in multiple countries was the worst since records began and led to the warmest summer on the continent for at least 500 years.

While critics and supporters of global climate change on both sides of the fence argue about the reasons for the changing weather, the latest and ongoing research leaves little doubt that the climate is affecting many changes, especially in agriculture. According to the updated 2012 EPA report, greenhouse gas concentrations in the atmosphere will continue to increase unless the billions of tons of annual emissions decrease substantially.

The study projects that increased concentrations of greenhouse gases are expected to increase Earth's average temperature, influence the patterns and amounts of precipitation, reduce ice and snow cover (as well as permafrost) raise sea levels, and increase the acidity of the oceans. Researchers say these changes will affect food supplies, water resources, infrastructure, ecosystems, and human health in the years ahead.

The study further indicates the magnitude and rate of future climate change will primarily depend on a number of factors, including: the rate at which levels of greenhouse gas concentrations in the atmosphere continue to increase; how strongly features of the climate –such  as temperature, precipitation, and sea level—respond to the expected increase in greenhouse gas concentrations; and, just as importantly, natural influences on climate—from volcanic activity and changes in the sun's intensity and natural processes within the climate system, such as changes in ocean circulation patterns.

According to the latest European study at Leeds and Reading, by the 2020s, hot days are expected to occur over large areas of Western Europe where previously they were uncommon, and unless farmers find ways to combat the heat stress that damages seed formation, yields of maize in France, for example, could fall by 12 percent compared to today.

The studies are the first global assessment of a range of climate change impacts—from increased flooding to rising demand for air conditioning—of how cutting carbon emissions could reduce these impacts.

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