Going to Extremes

By Bryan Walker 12/10/2012

Amidst the scarcely believable frenzy of climate change denial which has taken hold in sectors of American politics, to say nothing of the equally scarcely believable silence from the White House, we need to be reminded that there are sane and steady political voices in that country, however difficult it is for them currently to gain a hearing. Representatives Edward Markey and Henry Waxman recently had the minority staffs of the Committee on Natural Resources and the Committee on Energy and Commerce prepare a report for them Going to Extremes: Climate Change and the Increasing Risk of Weather Disasters (pdf here). It’s now available as a Kindle edition and in short compass reports the scientific case that global warming is shifting the odds towards extreme events.

Evidence is mounting alarmingly. Over the last several years a barrage of extreme weather events in the US and the world has been consistent with what scientists have been predicting from global warming. “Indeed this summer US weather was almost apocalyptic.” The introduction mentions some of the events of the past two years, noting that NOAA has recently concluded after looking through 50 years of weather data that droughts like the recent 2011 Texas drought are roughly twenty times more likely because of global warming. “Global warming has stacked the deck with extra jokers.”

The report zooms in on the multitude of extreme weather events in the US in 2012 which are consistent with scientists’ understanding that global warming is increasing the odds of heat waves, heavy precipitation, droughts and wildfires.

Extreme record-breaking temperatures abound. Drought has been severe in many states, with very adverse effects on crops.  Wildfires have been well above average in extent. Severe storms have hit in several areas. Low water levels have affected rivers. Water temperatures in the Great Lakes and the northeastern Atlantic have been exceptionally high. The total costs of 2012 extreme events are not yet known, but may rival the record $55 billion in 2011, also a year of severe weather disasters.

The US experience has been part of many global weather extremes in recent times, some of which are briefly highlighted in the report.

The predictions of scientists are outlined. Global warming will bring more record-breaking heat, with deleterious effects on food and agriculture production, human health and tourism. Regional rainfall patterns will alter with dry areas getting drier and wet areas wetter. There will be larger, longer-lasting and more damaging wildfires. Global food security may be threatened.

The report concludes:

The links between climate change and extreme weather are abundant, robust and well-documented in peer-reviewed scientific studies. The authoritative science organisations active in the relevant disciplines, including NASA, NOAA and the US National Academy of Sciences, have consistently confirmed the connections between climate change and extreme weather.

Many types of extreme weather, like heavy downpours and heatwaves, have increased in severity and frequency across the globe in recent years. This increase is directly linked to the changes in the Earth’s climate system driven by heat-trapping gases from burning fossil fuels.

…Climate change has contributed to shattered records and unprecedented weather catastrophes, like those the United States has experienced this summer.

There’s nothing in the report to surprise those who regularly follow what scientists are saying on the subject, and many of the footnoted references will be familiar to Hot Topic readers. The report’s significance is in its provenance, revealing that at least some US politicians wish to treat climate science seriously. The attribution of weather events to human-caused climate change is not a simple matter because of natural weather variability and the part played by natural factors such as El Nino and La Nina. But the report follows the careful science which considers it is now able to discern shifts in the frequency and severity of extreme weather events that evidence the effects of global warming.

Markey and Waxman have done nothing more than pay rational attention to well-attested science. Why that should appear politically combative is a question that only the proponents of denial and delay can answer, and what one sees of their answers contains little or no reference to the actual work that scientists are engaged in. It’s hard to see a way forward on the US political front as it is presently configured, but good to see the steadfastness of the two congressmen in representing the reality with which the country will eventually have to deal.