Mike Mann on the New Math of Extremes

August 6, 2012

Above, the most recent “This is Not Cool” drought update.

The Daily Climate:

The first scientist to alert Americans to the prospect that human-caused climate change and global warming was already upon us was NASA climatologist James Hansen. In a sweltering Senate hall during the hot, dry summer of 1988, Hansen announced that “it is time to stop waffling…. The evidence is pretty strong that the [human-amplified] greenhouse effect is here.”

At the time, many scientists felt his announcement to be premature. I was among them.

I was a young graduate student researching the importance of natural – rather than human-caused – variations in temperature, and I felt that the “signal” of human-caused climate change had not yet emerged from the “noise” of natural, long-term climate variation. As I discuss in my book, The Hockey Stick and the Climate Wars, scientists by their very nature tend to be conservative, even reticent, when it comes to discussing findings and observations that lie at the forefront of our understanding and that aren’t yet part of the “accepted” body of scientific knowledge.

Dire warning

Hansen, it turns out, was right, and the critics were wrong. Rather than being reckless, as some of his critics charged, his announcement to the world proved to be prescient – and his critics were proven overly cautious.

Given the prescience of Hansen’s science, we would be unwise to ignore his latest, more dire warning.

In a paper published today in the prestigious journal Proceedings of the National Academy of Sciences, Hansen and two colleagues argue convincingly that climate change is now not only upon us, but in fact we are fully immersed in it. Much of the extreme weather we have witnessed in recent years almost certainly contains a human-induced component.

Hansen, in his latest paper, shows that the increase in probability of hot summers due to global warming is such that what was once considered an unusually hot summer has now become typical, and what was once considered typical will soon become a thing of the past – a summer too improbably cool to anymore expect.

The time for debate about the reality of human-caused climate change has now passed.

We need to view this summer’s extreme weather in this wider context.

Not random

It is not simply a set of random events occurring in isolation, but part of a broader emerging pattern. We are seeing, in much of the extreme weather we are experiencing, the “loading of the weather dice.” Over the past decade, records for daily maximum high temperatures in the U.S. have been broken at twice the rate we would expect from chance alone. Think of this as rolling double sixes twice as often as you’d expect – something you would readily notice in a high stakes game of dice. Thus far this year, that ratio is close to 10 to 1.  That’s double sixes coming up ten times as often as you expect.

So the record-breaking heat this summer over so much of the United States, where records that have stood since the Dust Bowl years of the 1930s are now dropping like flies, isn’t just a fluke of nature; it is the loading of the weather dice playing out in real time.

The record heat – and the dry soils associated with it – played a role in the unprecedented forest fires that wrought death and destruction in Colorado and New Mexico. It played a role in the hot and bone-dry conditions over the nation’s breadbasket that has decimated U.S. agricultural yields. It played a role in the unprecedented 50 percent of the U.S. finding itself in extreme drought.

Other threats

Climate change is also threatening us in other ways of course, subjecting our coastal cities to increased erosion and inundation from rising sea level, and massive flooding events associated with an atmosphere that has warmed by nearly 2˚F, holding roughly 4 percent more water vapor than it used to – water vapor that is available to feed flooding rains when atmospheric conditions are right.

The state of Oklahoma became the hottest state ever with last summer’s record heat. It is sadly ironic that the state’s senior senator, Republican James Inhofe, has dismissed human-caused climate change as the “greatest hoax ever perpetrated on the American people.” Just last week he insisted that concern over the impacts of climate change has “completely collapsed.” This as Oklahoma City has just seen 18 days in a row over 100˚F (with more predicted to follow), Tulsa saw 112˚F Sunday, and 11 separate wildfires are burning in the state, with historic Route 66 and other state highways and interstates all closed.

The time for debate about the reality of human-caused climate change has now passed. We can have a good faith debate about how to deal with the problem – how to reduce future climate change and adapt to what is already upon us to reduce the risks that climate change poses to society. But we can no longer simply bury our heads in the sand.


13 Responses to “Mike Mann on the New Math of Extremes”

  1. mrsircharles Says:

    “The time for debate about the reality of human-caused climate change has now passed.”

    It’s overdue to move on from that. These die-hard deniers will probably never give up. But the decent world has to move on now and develop and invest in renewable energy for the goodness of our future. The future of all of us!

  2. […] Mike Mann on the New Math of Extremes […]

  3. rayduray Says:

    Ecologies are collections of biological species interacting in vast webs of life. This is what I see as being so important about the recent fish kills across the drought areas of the U.S. this summer:


    One of the most absolutely bizarre things I read today was some journalist dufus commenting that there is probably a $10 Million economic hit to the Midwestern caviar industry because so many sturgeon have died in the past few weeks. This supercilious savant seemed completely oblivious to the idea that it might just be a wise course to allow the sturgeon to breed, instead of providing little cocktail party hors d’oeurves for the vacuous celebrity elite in our gated enclaves for the 1%.

    Sometimes it seems that the willful and intentional ignorance, not to mention the stupidity, of the American media is beyond belief. Then I reel myself back to reality and have to admit that the only reason for a media in America today is to serve the interests of the banker and corporate elite. Who will have their caviar, damnit. Because “let them eat cake” just isn’t good enough if your name is Hilton, Corzine or Madoff.

  4. Martin Lack Says:

    Exactly what will it take for people in Oklahoma to vote Senator In-a-trough out of office?

    • rayduray Says:

      Re: “Exactly what will it take for people in Oklahoma to vote Senator In-a-trough out of office?”

      A candidate who is more right wing than Inhofe.

      • For those you who are not in the US, this is more an accurate statement than a joke.

        Just south to the state of Texas, THE REPUBLICAN PARTY OF TEXAS 2012 platform

        “We oppose the teaching of Higher Order Thinking Skills (HOTS) (values clarification), critical thinking skills and similar programs that are simply a relabeling of Outcome-Based Education (OBE) (mastery learning) which focus on behavior modification and have the purpose of challenging the student’s fixed beliefs and undermining parental authority.”

        It would appear that if they moved any further right that they would fall of the right side of their flat earth.

        • rayduray Says:

          Well that’s a zinger. I hadn’t read up on Texas having the HOTS for OBE Wan-Kenobi.

          But I did read about the extreme right winger David Dewhurst was defeated by the batshit crazy right winger Ted Cruz down in Texas last week.

          That’s why I said the only way Inhofe gets defeated is by the Second Coming of Adolf Hitler. OK, that’s bad. I’m introducing Godwin’s Law here. Let me relent. They don’t need Adolf. Any typical Joe Arpaio type will do.

      • Martin Lack Says:

        If so, the majority in Oklahoma must simply be insane.

  5. guylacrosse Says:

    Go look at Inhofe’s campaign contributions to see why he behaves as irrationally as he does. His campaign is largely financed by Koch industries.


    This guy is basically just a mouthpiece of the oil & gas industry. They tell him what to say and he does it.

  6. guylacrosse Says:

    I think raising awareness about global warming will help to create more opposition to oil, coal & gas sponsored candidates. They will initially need a lot of support to overcome the money those industries can throw at campaigns.

    Oklahoma is probably a lot like Kansas (see: What’s the matter with Kansas?) for reference. They basically campaign on emotional, faith-based issues then serve the special interests that bank-rolled their campaigns once in office.

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