Hansen Breaks the Taboo

Hansen breaks the single-event attribution taboo in a Washington Post op-ed:

In a new analysis of the past six decades of global temperatures, which will be published Monday, my colleagues and I have revealed a stunning increase in the frequency of extremely hot summers, with deeply troubling ramifications for not only our future but also for our present.

This is not a climate model or a prediction but actual observations of weather events and temperatures that have happened. Our analysis shows that it is no longer enough to say that global warming will increase the likelihood of extreme weather and to repeat the caveat that no individual weather event can be directly linked to climate change. To the contrary, our analysis shows that, for the extreme hot weather of the recent past, there is virtually no explanation other than climate change.

The deadly European heat wave of 2003, the fiery Russian heat wave of 2010 and catastrophic droughts in Texas and Oklahoma last year can each be attributed to climate change. And once the data are gathered in a few weeks’ time, it’s likely that the same will be true for the extremely hot summer the United States is suffering through right now.

These weather events are not simply an example of what climate change could bring. They are caused by climate change.

(emphasis added)


(Borehole items)

Comments:

  1. Meanwhile NASA give Christy a forum to say its all just "weather".

    http://science.nasa.gov/science-news/science-at-nasa/2012/03aug_summer2012/

    Paul

  2. Not to mention the heatwave and droughts across the USA in the 1930s... That was even more definite proof of climate change.

    • If you read carefully, you'll see that Hansen withheld judgment on this year. The three events he notes as attributable were without any observed precedent whatsoever.

    • Well... there was a pretty bad drought in Texas and Oklahoma in the 1930s - so that really has happened before - resulted in the Okies from Muskoki moving to California in Steinbeck.

      I think this an observed precedent, no?

      This is proof of global warming climate change now going on for 80 years!!

      • It's Muskogee, by the way. I actually passed through it on Monday. (It's on the most direct route to Austin from Chicago.) It was a cool 106 F at the time, but every day since then it has been over 110 F.

  3. IIRC Hansen first broached the 3-sigma approach to attribution a while back, so AFAICT what's new here is the finger being pointed at additional recent events (and of course anticipating being able to make the same finding for the current NA drought/heat). Less substantively, shifting one of the four warming faces to extreme is also new.

    Re Christy, I decided quite some time ago that any scientist who complains about statements like Hansen's without having long ago done everything they could to strip away Christy's veneer of respectability is simply a hypocrite. Sure, many with that view are perhaps a little surprised to be thrust into the spotlight as the climate continues to get nastier, but if they're uncomfortable with that role they should just STFU rather than engage in a public display of reticence. /rant

  4. Is global warming only defined by weather in the USA? Because a lot of the world is cold and wet, not hot and dry.
    If Global Warming also causes wet and damp, what if the entire world was wet and damp for say, 50 years. Would that still be global warming?

    • "Global Warming", properly speaking, is a number. It cannot "cause" anything. If the entire world were cool for 50 years there would be no global warming, obviously.

      That would not exclude an anthropogenic component to the change. But either way that's a wild hypothetical. Nothing of the sort is happening. The July maps are not out yet. Here is what June looked like: http://www.ncdc.noaa.gov/sotc/service/global/map-blended-mntp/201206.gif

      Regardless, you are missing the point of the Hansen paper. I suggest you read it. http://arxiv.org/pdf/1204.1286v1.pdf

  5. That data representation only reflects anomalies compared to 1971 to 2001 - presumably there were weather and climate differences before then.
    What would the chart look like if the base period were 1101 to 2001?

    [ What do you think? Please do some research and get back to us. -mt ]


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