Temperature and extreme weather

2008-08-11

in Economics, Politics, Science, The environment

A new article in Science provides observational evidence of the link between rising temperatures and extreme weather events:

These observations reveal a distinct link between rainfall extremes and temperature, with heavy rain events increasing during warm periods and decreasing during cold periods. Furthermore, the observed amplification of rainfall extremes is found to be larger than predicted by models, implying that projections of future changes in rainfall extremes due to anthropogenic global warming may be underestimated.

Of all the impacts of climate change, extreme weather seems especially likely to help spur mitigation action, especially when that weather occurs in rich states. Reasons for that include the visibility and newsworthiness of floods, droughts, hurricanes, and so forth. Another major factor is the importance of the insurance industry, especially insofar as their professional estimations of risk affect the cost and feasibility of different projects. That is, so long as policy-makers do not establish incentives for risky behaviour.

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. November 22, 2011 at 9:38 pm

Climate Panel Says To Prepare For Weird Weather

“Extreme weather, such as the 2010 Russian heat wave or the drought in the horn of Africa, will become more frequent and severe as the planet warms, the Intergovernmental Panel on Climate Change (IPCC) warns in a report released today. Some areas could become ‘increasingly marginal as places to live in,’ the report concludes. Critics of the report note that ‘Governments have in the past considerably weakened the language of IPCC summaries for policymakers,’ and that the IPCC process tends to water down even the most obvious conclusions.”

. August 2, 2017 at 3:37 pm

Millions of people living in South Asia face a deadly threat from heat and humidity driven by global warming according to a new study.

Most of India, Pakistan and Bangladesh will experience temperatures close to the limits of survivability by 2100, without emissions reductions.

The research says the fraction of the population exposed to dangerous, humid heat waves may reach 30%.

South Asia is home to one-fifth of the world’s inhabitants.

Most official weather stations around the world measure temperature with two thermometers.

The first, or “dry bulb” instrument, records the temperature of the air. The other, or “wet bulb” thermometer, measures relative humidity in the air and the results are normally lower than just the pure air temperature.

For humans, this wet bulb reading is critically important.

While the normal temperature inside our bodies is 37C, our skin is usually at 35C. This temperature difference allows us to dissipate our own metabolic heat by sweating.

However, if wet bulb temperatures in our environment are at 35C or greater, our ability to lose heat declines rapidly and even the fittest of people would die in around six hours.

While a wet bulb 35C is considered the upper limit of human survivability, even a humid temperature of 31C is considered an extremely dangerous level for most people.

Recorded wet bulb temperatures on Earth have rarely exceeded 31C. However, in 2015 in Iran, meteorologists saw wet bulb temperatures very close to 35C. In the same summer, a deadly heat wave killed 3,500 people in India and Pakistan.

This understanding of the potentially deadly impact on humans of wet bulb temperatures is key to this new study.

. August 15, 2017 at 10:34 am
. August 29, 2017 at 5:43 pm

Harvey marks the most extreme rain event in U.S. history

The rain from Harvey is in a class of its own. The storm has unloaded over 50 inches of rain east of Houston, the greatest amount ever recorded in the Lower 48 states from a single storm. And it’s still raining.

John Nielsen-Gammon, Texas state climatologist, said a rain gauge in Mont Belvieu, about 40 miles east of Houston, had registered 51.9 inches of rain through late Tuesday afternoon. This total exceeds the previous record of 48 inches set during tropical cyclone Amelia in Medina, Texas in 1978.

. September 12, 2017 at 8:13 pm

The world’s average temperature is between 0.6 and 0.7°C (1.1- 1.3°F) higher than it was in 1979. Scientists have understood since the 1850s that hotter air holds more water vapour; a law known as the Clausius-Clapeyron equation states that for every degree Celsius of warming, the atmosphere will hold 7% more moisture. In 1989 two Japanese researchers used computers to model this phenomenon and concluded that this wetter air would lead to more of the heaviest rains rather than, say, near-perpetual drizzle. It is thus no surprise that insurers see an increase in water-related disasters.

Other lines of evidence bear out the insurers’ loss data. In 2015 researchers from the Potsdam Institute for Climate Impact Research in Germany compared computer models of the atmosphere as it now is and as it used to be to see how much of an impact these effects might be having. They found that the planet Earth experienced 12% more record-breaking downpours between 1980 and 2010 than might have been expected had the climate not been changing. The same year Reto Knutti and Erich Fischer at ETH Zurich, a Swiss university, found that the warming recorded since pre-industrial times made new one-day records for rainfall over land 18% more likely. For 2°C of warming, the target below which countries vowed to keep global warming under the Paris agreement of 2015, the figure would rise to 40%.

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