Policy Documents

Global Warming Alarmists Crying Wolf Regarding Australia Floods

James M. Taylor –
January 14, 2011

Global warming alarmists are crying wolf again, this time regarding flooding in eastern Australia. Scientific evidence, however, clearly shows the alarmists are playing fast and loose with the facts.

Pointing Finger at Global Warming
ABC News has published an article this morning titled, “Raging Waters in Australia and Brazil Product of Global Warming.” The article states, “The decade that just ended saw nine of the 10 warmest years on record, and warmer temperatures mean more moisture in the air. That moisture can fall as torrential, flooding rains in the summertime or blizzards in the winter.”

Quoting prominent global warming activist Richard Somerville, a professor at the University of California at San Diego, ABC News reports, “Because the whole water cycle speeds up in a warming world, there's more water in the atmosphere today than there was a few years ago on average, and you're seeing a lot of that in the heavy rains and floods for example in Australia.”

NASA Says Otherwise
Scientists at NASA, however, have identified a different reason.

"The copious rainfall is a direct result of La Nina's effect on the Pacific trade winds and has made tropical Australia particularly rainy this year,” said NASA oceanographer David Adamec in a press statement.

The southern Pacific Ocean periodically undergoes El Nino (warmer) and La Nina (cooler) conditions. This year the Pacific Ocean is undergoing a particularly strong La Nina, which delivers heavy rainfall to areas that are normally dry, such as Brisbane, Australia.

Floods, Droughts Nothing New
Of course, there will always be droughts, floods, heat waves, cold snaps, blizzards, and other “extreme” weather conditions occurring somewhere on the planet. These events provide a never-ending opportunity for deceitful propaganda campaigns intended to fool people into believing global warming is causing a new crisis every week.

Take, for instance, the ABC News claim that global warming is causing the Australian floods. Even forgetting what we know about the current La Nina conditions, the ABC News claim is preposterous on its face.

First, global warming alarmists have spent the past several years telling us that global warming is causing less rain – not more rain – in Australia. Less than a year ago, for example, USA Today published an article titled, “Global Warming Likely Cause of Australia’s Drought.” So which is it? Is global warming causing more rain or less rain? Alarmists can’t have it both ways.

Second, the trite response that global warming causes more droughts and more floods is soundly contradicted by the scientific evidence.

Droughts Becoming Rare
Regarding drought, there is overwhelming scientific evidence that droughts are becoming less frequent and less severe.

A 2004 study of Northern Hemisphere soil moisture published in the peer-reviewed International Journal of Climatology reports, “The terrestrial surface is both warmer and effectively wetter … A good analogy to describe the changes in these places is that the terrestrial surface is literally becoming more like a gardener’s greenhouse.”

A 2006 study published in the peer-reviewed Geophysical Research Letters reports, “An increasing trend is apparent in both model soil moisture and runoff over much of the U.S. … This wetting trend is consistent with the general increase in precipitation in the latter half of the 20th century. Droughts have, for the most part, become shorter, less frequent, and cover a smaller portion of the country over the last century.”

And a 2006 study published in the peer-reviewed Journal of Hydrology reports, “Evidence indicates that summer soil moisture content has increased during the last several decades at almost all sites having long-term records in the Global Soil Moisture Data Bank.”

No Increase in Floods
Regarding floods, scientific evidence shows a moderate increase in 20th century precipitation is occurring in a benign manner that is not producing more flooding events.

For example, a 1999 study in the peer-reviewed Geophysical Research Letters examined U.S. flood events throughout the 20th century. The study found a moderate rise in overall precipitation during the 20 century but a decline in extreme weather events, such as floods. “The conterminous U.S. is getting wetter, but less extreme.”

The results of the Geophysical Research Letters study were confirmed in 2009 by a study published in the peer-reviewed Journal of the American Water Resources Association. The study found a moderate increase in 20th century precipitation and 20th century river and stream flows, but the increase in river and stream flows did not translate into more floods. Instead, the rivers and streams gained water primarily during their low-flow seasons.

“There is broad evidence … for increased magnitudes of low and moderate flows both regionally and nationally,” while “trends in high flows have been much less evident,” the study reported.

“At a national scale, only a small proportion of the gages measuring dominantly natural streamflow … show upward trends in the annual maximum average daily discharge,” the study explained.

Indeed, National Climatic Data Center precipitation records show the largest increase in precipitation has occurred during the fall dry season, which has served to prevent or alleviate droughts. By contrast there has been essentially no increase in precipitation during the winter and spring flood seasons. 
 
Bursting the Alarmist Bubble
Rather than global warming causing more drought and more floods, the scientific evidence clearly shows global warming is causing less frequent drought and no increase in floods. Droughts and floods, like the floods currently occurring in eastern Australia, will always occur somewhere on earth, but they are decidedly not caused by global warming.