Tiempo Climate Newswatch

Testifying to a congressional committee, Lisa Jackson, head of the United States Environmental Protection Agency (EPA), has attacked a draft bill, the Energy Tax Prevention Act of 2011, that aims to limit the EPA's powers to control greenhouse gas emissions. The EPA bases its authority in this area on a 2007 Supreme Court judgement that greenhouse gases had the potential to damage human health and well-being. "[The] bill would, in its own words, 'repeal' the scientific finding regarding greenhouse gas emissions," she said. "Politicians overruling scientists on a scientific question - that would become part of this committee's legacy," she continued.

The EPA's mandate is also being challenged at state level. Texas is challenging the rules in six lawsuits that are pending in federal appeals courts. Greg Abbott, Texas attorney general, has said that he would abandon the litigation if Congress passed legislation to block the EPA or if the administration backed down. "The EPA is acting in a way unconstrained by the Clean Air Act and causing industry as well as the states to have to deal with a moving target," he said. "We don't know if the administrative rules they've issued today are going to be the same ones they will issue tomorrow. We keep getting the impression they will keep coming up with new and ever-shifting and changing rules."

A new study from the United States centre of the Stockholm Environment Institute (SEI-US) shows that climate change will aggravate water problems in the American Southwest, increasing the long-term shortfall caused by population and economic growth by up to a quarter. It could add up to US$1 trillion in extra costs over the coming 100 years. Rising temperatures will drive up demand in all areas, particularly in agriculture, and create intense competition for dwindling resources.

"Climate change is affecting Americans in many areas; the water crisis in the Southwest is one of the clearest examples," said lead author Frank Ackerman from the Climate Economics Group at SEI-US. "Climate policy choices we make today are not just about exotic environments and far-future generations – they will help determine how easy or hard it is to create a sustainable water system in the most arid region of the country."

The current La Niña event will be weakening in coming months, but its ability to last into the summer is uncertain, according to the United States Climate Prediction Center. "A majority of the models predict a return to neutral conditions by May-June-July 2011, although some models [predict] a weaker La Niña into the summer," the latest update states.

The 2010/11 event has been particularly intense. "In atmospheric terms it has to be termed one of the strongest ever La Niña episodes," reports Rupa Kumar Kolli, of the World Meteorological Organization. As well as flooding in Australia, the disruption in tropical and subtropical climates caused by La Niña has been responsible for extreme conditions in Asia, Africa and South America. Chile has put in place nationwide contingency plans in preparation for the impact of La Niña-induced drought.