Just days after Senator James Inhofe (Republican, Oklahoma) said he could not find one conclusion of the Intergovermental Panel on Climate Change (IPCC) that “has now not been refuted,” Oklahoma City yesterday (14 June 2010) experienced its heaviest rain in history. In 2007, the IPCC concluded that “the frequency of heavy precipitation events has increased over most land areas, consistent with warming and observed increase of atmospheric water vapor.” It furthermore warned that it was “very likely” that the trend would continue during this century. [Re-posted from World Wildlife Fund Climate Blog posting of 15 June 2010]
[Thanks to Nick Sundt at WWF Climate Blog for developing this post.]
Environmental Protection Agency Finds that Greenhouse Gas Emissions Increase Risks of such Events and therefore Endanger Public Health and Welfare
Based in part on the IPCC's findings, the U.S. Environmental Protection Agency concluded at the end of 2009:
"Water resources across large areas of the country are at serious risk from climate change, with effects on water supplies, water quality, and adverse effects from extreme events such as floods and droughts. Even areas of the country where an increase in water flow is projected could face water resource problems from the supply and water quality problems associated with temperature increases and precipitation variability, as well as the increased risk of serious adverse effects from extreme events, such as floods and drought. The severity of risks and impacts is likely to increase over time with accumulating greenhouse gas concentrations and associated temperature increases and precipitation changes. "
EPA made that statement in its Endangerment and Cause or Contribute Findings for Greenhouse Gases under the Clean Air Act, commonly referred to as its "endangerment finding," a document that constitutes the basis for the Federal government's planned regulations to curb greenhouse gas emissions.
Last Thursday (10 June 2010), Senator Inhofe argued before the Senate that the EPA endangerment finding should be formally rejected by the Senate, saying that "I do not believe that" greenhouse gases contribute to climate change and that the science "has been pretty much debunked." The other Oklahoma senator, Coburn, said during the debate that "this is not settled science" and referred to the "incompetency at the EPA."
Neither Senator acknowledged the threat posed by climate change and the need for climate change preparedness in Oklahoma. Both voted in support of the Murkowski Resolution which -- had it passed -- would have effectively vetoed EPA's science based findings. (see Senate Resolution to Strip EPA of Power to Regulate Climate Change Pollution is Defeated, 10 June 2010; and Video and Transcript of Senate Debate on Murkowski Resolution to Veto EPA's Science-Based Climate Change Findings, 12 June 2010).
Their remarks echoed those of Congressman John Sullivan (Republican, Oklahoma) last December at the international climate change negotiations in Copenhagen, Denmark. He said the negotiations were based on "science that is fraudulent."
IPCC Findings Reaffirmed by the National Research Council
In fact, the science is not fraudulent and has not been debunked. To the contrary, the National Research Council just last month (May 2010) affirmed the IPCC's conclusions. Here is what the NRC concluded in its report, Advancing the Science of Climate Change:
"Global precipitation and extreme rainfall events are increasing. In general, changes in precipitation are harder to measure and predict than changes in temperature. Nevertheless, some conclusions and projections are robust. For example, based on the fundamental properties and dynamics of the climate system, it is expected that the intensity of the global water cycle and of precipitation extremes (droughts and extremely heavy precipitation events) should both increase as the planet warms. Increases in worldwide precipitation and in the fraction of total precipitation falling in the form of heavy precipitation have already been observed—for example, the fraction of total rainfall falling in the heaviest one percent of rain events increased by about 20 percent over the past century in the United States. Climate models project that these trends, which create challenges for flood control and storm and sewer management, are very likely to continue."
And the NRC said:
"Droughts and floods are likely to increase. Given the observed increases in heavy precipitation events and the expectation that this intensification will continue, the risk from floods is projected to increase in the future."
Expert at National Center for Atmospheric Research: Increased Water Vapor in Atmosphere Exerts "Systematic Influence" on Weather Events
In Joe Romm's Exclusive interview: NCAR’s Trenberth on the link between global warming and extreme deluges, posted at Climate Progress, Dr. Kevin Trenberth, head of the Climate Analysis Section at the National Center for Atmospheric Research comments on the increase in extreme precipitation events. While acknowledging that "you can’t attribute a single event to climate change," Trenberth says that "there is a systematic influence on all of these weather events now-a-days because of the fact that there is this extra water vapor lurking around in the atmosphere than there used to be say 30 years ago. It’s about a 4% extra amount, it invigorates the storms, it provides plenty of moisture for these storms and it’s unfortunate that the public is not associating these with the fact that this is one manifestation of climate change."
Oklahoma Climatological Survey: Expect More Intense Rain Events
Among those warning of the consequences of climate change, and specifically of more extreme precipitation events, is none other than the Oklahoma Climatological Survey. In its Statement on Climate Change and its Implications for Oklahoma, the survey said in 2007 that it expected "individual rain events will become more intense" and "more runoff and flash flooding will occur" under the projected range of climate change in the 21st century.
Projected impacts of climate change on Oklahoma (click on image for larger version). Source: Oklahoma Climatological Survey.
Oklahoma City Deluge
Against the backdrop of mounting scientific evidence came yesterday's rains in Oklahoma City. Jeff Masters at the Weather Underground describes what happened in his posting today, Heaviest 1-day rain in Oklahoma City history:
"Oklahoma City's rainiest day in history brought rampaging floods to the city and surrounding areas yesterday, as widespread rain amounts of 8 - 11 inches deluged the city. Fortunately, no confirmed deaths or injuries have been blamed on the mayhem, though damage is extensive. Oklahoma City's Will Rogers Airport received 7.62" of rain yesterday, smashing the record for the rainiest day in city history. According to the [National Weather Service] ...the city's previous rainiest day occurred September 22, 1970, when 7.53 inches fell. Some rivers continue to rise due to all the rain, and the Canadian River east of downtown Oklahoma City is four feet over flood stage, with major flooding expected today. You can track the flooding using our wundermap with the USGS Flood layer turned on."
The heavy rains and flooding, which extend well beyond Oklahoma City, have prompted the state to declare emergencies in 59 Oklahoma counties. See the situation update from the Oklahoma Department of Emergency Management, Impacts of Severe Flooding Continue for State (15 June 2010)
Jeff Masters: Numerous Floods this Year Associated with Record-breaking Warm Temperatures
In his posting, Jeff Masters puts the Oklahoma events into the larger context:
"We've had an inordinate number of severe floods in the U.S. so far this year. The worst was the May Tennessee flood, which killed 31 people--the highest death toll from a non-tropical cyclone flooding event in the U.S. since 1994, and the most devastating disaster in Tennessee since the Civil War. The Tennessee floods were rated as a 1000-year flood for Middle Tennessee, West Tennessee, South Central and Western Kentucky and northern Mississippi. Two-day rain totals in some areas were greater than 19 inches.Last Friday's disastrous flash flood in Albert Pike Recreation Area, Arkansas, killed twenty people. That flood was triggered by 8+ inches of rain that fell in just a few hours over the rugged mountains west of Hot Springs. And in March, record rains from a slow-moving and extremely wet Nor'easter triggered historic flooding in Rhode Island and Southeastern Massachusetts, with several rivers exceeding their 100-year flood levels. The 16.32" of rain that fell on Providence, Rhode Island, made March that city's wettest month in recorded history.
All of these flooding events were associated with airmasses that brought record-breaking warm temperatures to surrounding regions of the country. For example, during the overnight hours when the June 11 flood in Arkansas occurred, fifty airports in the Southern and Midwestern U.S. had their highest minimum temperatures on record. During the 1000-year flood in Tennessee, 51 warm minimum temperatures records were set in the eastern half of the U.S. on May 1, and 97 records on May 2. Rhode Island's record wettest March also happened to be its record warmest March. And the air mass that spawned yesterday's Oklahoma City floods set record warm minimum temperatures at 22 airports across the central and Eastern portions of the U.S. on Monday. All this is not surprising, since more moisture can evaporate into warmer air, making record-setting rainfall events more likely when record warm temperatures are present. The total number of airports in the U.S. considered for these comparisons is around 500, so we're talking about significant portions of the U.S. being exposed to these record-breaking warm airmasses this year. For the spring months of March - May, it was the 21st warmest such period in the 116-year record, according to the National Climatic Data Center. At the 500 or so largest airports in the U.S., daily high temperature records outnumbered low temperature records by about a factor 2.5, 1200 to 508. Record high minimums this spring outnumbered record low maximums by 1163 to 568. So far in June, record daily highs have outpaced record lows by 176 to 13, and record high minimums have outpaced record low maximums, 419 to 62."