Repeated, record-breaking rainfall events increase with global warming

Click to enlargeSean R. Heavey

Heavy rainfall events setting ever new records have been increasing strikingly in the past thirty years. While before 1980, multi-decadal fluctuations in extreme rainfall events are explained by natural variability, a team of scientists of the Potsdam Institute for Climate Impact Research detected a clear upward trend in the past few decades towards more unprecedented daily rainfall events.

They find the worldwide increase to be consistent with rising global temperatures which are caused by greenhouse-gas emissions from burning fossil fuels…

The average increase is 12 percent globally – but 56 percent in South East Asia

An advanced statistical analysis of rainfall data from the years 1901 to 2010 derived from thousands of weather stations around the globe shows that over 1980-2010 there were 12 percent more of these events than expected in a stationary climate, a scenario without global warming. “Due to the upward trend, the worldwide increase of record-breaking daily rainfall events in the very last year of the studied period reaches even 26 percent”, Lehmann adds.

The record-breaking anomaly has distinct patterns across Earth’s continents with generally wet regions seeing an over-proportional increase and drier regions less so. In South East Asian countries the observed increase in record-breaking rainfall events is as high as 56 percent, in Europe 31 percent, in the central US 24 percent. In contrast, some regions experienced a significant decrease of record-breaking daily rainfall events. In the Mediterranean, the reduction is 27 percent, and in the Western US 21 percent. Both regions are at risk of severe droughts.

While a statistical analysis of course cannot provide direct physical cause-effect relations, the scientists compared their findings to existing knowledge about how much more water can be stored in the atmosphere when temperatures rise, as given by the well-known Clausius-Clapeyron equation. This additional moisture can be released during short-term heavy rainfall events. The scientists show that the observed increase in unprecedented heavy rainfall events generally fits with this thermodynamically expected increase under global warming…

Up to now, studies could add up to only medium confidence on how human induced greenhouse gases have contributed to changes in heavy precipitation events at the global and regional scale. The new analysis now helps to fill this research gap. Building on previous work on extreme precipitation, it is the first to study worldwide observational data of record-breaking daily rainfall events in this context.

I probably haven’t said this for at least 10 minutes, but — if I was starting out, today, I’d point myself at a geek career in computational analysis. This stuff is fascinating. Most particularly when you have the opportunity to gather wide-reaching data and spend time data-mining, winnowing away the chaff – perhaps discovering a new direction, insight to old problems.

10 thoughts on “Repeated, record-breaking rainfall events increase with global warming

  1. Nikohl Vandel says:

    Reblogged this on Niki.V.all.ways.My.way. and commented:
    So, I guess I just want to know . . . when are the so-called “Presidential” contenders going to even begin to talk about a plan of action? The only real contender I see that can handle this mess is #DrJillStein and perhaps that Governor from New Jersey, he at least knows to get out of the way of mother nature! Sigh, still no one really REALLY talking about the rising waters and what we should be looking forward to in the next decade. I mean, I know us smart people are all talking about it all the time, but you know . . . Like on CNN — asking those wannabes, “WTF are you going to do to save Virginia Beach?!”

  2. Nevermind says:

    Scientists used the CIA’s Medea program to study how global warming could worsen conflict. Under pressure from a group of congressional Republicans that project has come to an end. (May 21, 2015) “Over the past several years, climate change has gained prominence among defense experts, many of whom see it as a “threat multiplier” that can exacerbate crises such as infectious disease and terrorism. Medea had been part of a larger network of climate-related initiatives across the national security community. Medea’s closure notwithstanding, that network appears to be growing. Last fall, Obama issued an executive order calling on federal agencies to collaborate on developing and sharing climate data and making it accessible to the public.”

  3. Antediluvian says:

    Major interstate closed ‘completely and indefinitely’ as heavy rain in California desert collapses bridge (July 20, 2015) The rains came amid a second day of showers and thunderstorms in southern and central California that were setting rainfall records in what is usually a dry month. Saturday’s rainfall broke records in at least 11 locations, including five places that had the most rain ever recorded on any day in July, according to the National Weather Service.

    • Attrition says:

      The interstate bridge that washed out in the desert between Los Angeles and Phoenix easily withstood its daily load of thousands of cars and trucks, but it failed when the pounding of a powerful flash flood scoured away land where the bridge was anchored, officials said Monday.
      The flood severed a highway vital to the movement of people and commerce between two of the nation’s largest cities. On an average day, Interstate 10 carries about 27,000 vehicles in either direction where the bridge failed.
      Water rushing through a normally dry desert gully eroded the land around the bridge, causing one side of the eastbound span to collapse and forcing the closure of the westbound span.
      While the bridge should have been fine if the flood came straight down the gully, this time it swept through at an angle that pushed the water to one bank, digging away the soil at the gully’s edge where the bridge reconnected with the road bed, California Department of Transportation spokeswoman Vanessa Wiseman said.
      Caltrans was not yet sure why the flow followed that path, but such redirections are not unusual in sandy desert soil, she said.
      Nine inspectors fanned out Monday to check all 44 bridges along a 20-mile stretch of I-10 after a second bridge showed signs of damage following the storm Sunday, according to Caltrans. They also planned to inspect bridges across the large swath of Southern California where the remnants of a tropical storm off Baja California dumped unusual deluges this month.

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