The Coming Dust Bowl, USA

With more than 50 square kilometers of polar ice cap melting every single day, it's no wonder a new Dust Bowl is threatening the US. But the accelerating greenhouse effect will hit children and poor people most.

Global warming has been cited in numerous studies as the main cause for the dramatic climate changes Earth is witnessing nowadays, including the recent warm winter and the drought that affected Australia.

Global warming is defined as the observed increase in the average temperature of the Earth's near-surface air and oceans in recent decades and its projected continuation. It is responsible for the rapid melting of Earth's ice cap at the North Pole and for the proliferation of fungi (among others), that leads to a faster decomposition of leaves and dead tree-trunks.

A new study shows that global warming will also accelerate the proportions of the drought that affects the Southwest of the US, prompting for urgent measures to deal with the scanty water supplies in the region.

"The bottom line message for the average person and also for the states and federal government is that they'd better start planning for a Southwest region in which the water resources are increasingly stretched," said Richard Seager of Columbia University's Lamont Doherty Earth Observatory.

Seager's study was published in this week's edition of Science. The scientists in his team compared 19 computer models of the climate, including data that went back to the first weather recordings, in 1860. The projection in the future showed that the continuous drying of the Southwestern US and of some northern regions in Mexico- observed in the late 20th century- will not stop and is likely to continue at a faster pace.

The conclusions of Seager's study are in accordance with previous NASA findings, which cautioned that global warming might increase droughts across certain parts of the world, including the southwestern United States.

NASA researchers compared historical records of the climate impact of changes in the sun's output with model projections of how a warmer climate driven by greenhouse gases would change rainfall patterns. They found a warmer future climate likely will produce droughts in the same areas as those observed during ancient times but potentially with greater severity.

The reduction in rainfall could reach levels of the 1930s Dust Bowl that ranged throughout the Midwestern United States, Seager said in a telephone interview with AP.

Last winter, precipitation in the US was above average in the center, while large sections of the East, Southeast and West were drier than average. The global average temperature was the warmest on record for the December-February period. According to the U.S. Drought Monitor, 25 percent of the continental U.S. was in moderate-to-exceptional drought at the end of February. The most severe conditions were in southwest Texas, northern Minnesota, Wyoming and the western High Plains.

However, Seager cautioned that the dust storms reported in the '30 are not likely to occur in our times, because back then poor agricultural practices were involved too. But he added that the reduction in rainfall could be equivalent to those times when thousands of farmers abandoned their parched land and moved away in search of jobs.

Agriculture will still play a role in the 21st century Dust Bowl, since most of the water in the Southwestern US is used for irrigation. The problem gets bigger though when we consider the increasing urban population that needs clean water resources.

"So, in a case where there is a reduced water supply, there will have to be some reallocation between the users," Seager said. "The water available is already fully allocated."

The scientist suggested that a solution would be a concerted effort to reduce water consumption in agriculture (by withdrawing some land from the agricultural circuit) and conserving water in urban areas.

"But it's something that needs to be planned for," Seager said. "It's time to start thinking how to deal with that."

Jonathan T. Overpeck, director of the Institute for the Study of Planet Earth at the University of Arizona, cited by CNN, said the finding "agrees with what is already happening in the Southwest, and will be further complicated by the already declining spring snowpack due to warming."

"These are scary results, but scary in part because they are results of well thought-out scientific work by a large number of strong scientists," said Overpeck, who did not participate at the study.

The Chihuahua Desert straddling the U.S.-Mexican border is suffering from drought and intensive farming and overgrazing. North America's largest desert, the Chihuahua has 3,500 unique plant species, including an array of cactus and yucca, that could be at risk.

In a previous study published in 1997 in Science magazine, Richard Seager's team also showed that the eastern equatorial Pacific cooled during the 20th century.

A new UN climate report released Friday in Brussels projects that one-fifth of all animal and plant species are threatened with extinction if warming continues at the current pace.

Another report, cited by Reuters, showed also that up to 175 million children would be affected every year over the next decade by climate-related disasters like droughts, floods and storms.

That is 50 million a year more than in the 10 years to 2005. Being society's vulnerable members, children would be hurt disproportionately, and millions more would be killed, forced from their homes or hit by hunger and disease.

"The poorest of the poor in the world... are going to be the worst hit and are the most vulnerable in terms of impact of climate change," said Intergovernmental Panel on Climate Change chairman Rajendra Pachauri.