Real-time climate attribution arrives

Climate scientists are now able to tell whether climate change fuels temperature extremes in real time and even ahead of time, using forecast models, historical data and peer-reviewed research, Andrew writes.

Why it matters: A new product from Climate Central, a nonprofit research and journalism organization, marks a significant shift in thinking about the ties between daily weather and long-term climate change.

  • Presented in a compelling visual format accessible to the public and usable by TV meteorologists, the endeavor is known as the «Climate Shift Index,» or CSI.

Driving the news: Climate scientists have made great strides during the past decade in finding the human fingerprints in worsening or setting off extreme weather events, such as heat waves and extreme rainfall.

  • These studies, known as extreme event attribution, have taken place after a disaster, and involve sifting through complex historical data and computer model simulations.
  • Climate Central’s real-time effort is currently limited to just one important parameter: temperature.

Between the lines: Based on methods recently published in a peer-reviewed journal, the organization is using weather and climate models combined with other sources to place daily high and low temperatures in a climate change context.

  • The CSI tool, designed in conjunction with outside attribution experts, including Friederike Otto of Imperial College London, gives a number to indicate how frequently certain temperatures now occur in a warming world.

Zoom in: If the CSI level is above zero, it means that human-caused climate change has made a day’s temperature more common. A below-zero CSI reading would indicate climate change has made that day’s temperature more rare compared to a climate without human-caused warming.

  • CSI of 0means a climate change influence is “not detectable.”
  • The scale, from minus-5 to positive 5, is available for the previous day out to three days ahead.
  • A CSI value of 2 means the day’s temperature was made at least twice as likely to occur compared to a world without human-caused global warming.

How it works: Behind the CSI lies years of slowly advancing work in determining how climate change is stacking the deck in favor of more hot and fewer cold extremes.

  • To compute it, Climate Central uses two methods that it averages together. One utilizes 22 climate models, which are run with and without added greenhouse gases from human activities, and the other uses observational data.

What they’re saying: “This is a big step forward for operationalized event attribution,» Noah Diffenbaugh, a climate scientist at Stanford University who was not involved in the Climate Central effort, told Axios via email.

 Read the whole story.


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