comsc US Politics | AMERICAblog News: Hansen on 3°C: Quarter to half of species on earth may die from global warming
Join Email List | About us | AMERICAblog Gay
Elections | Economic Crisis | Jobs | TSA | Limbaugh | Fun Stuff

Hansen on 3°C: Quarter to half of species on earth may die from global warming

| Reddit | Tumblr | Digg | FARK

UPDATE: A complete list of climate series pieces is available here:
The Climate series: a reference post.

I promised in this post to write about James Hansen's new paper "The New Climate Dice" (pdf) — which has been making the rounds (for example, here and here).

Hansen is the head of the NASA Goddard Institute for Space Studies in New York City, and is a lead — if not "the" lead — American voice on the dangers of impending climate change.

You really should read his paper. And yes, it has started, the climate catastrophe.

How can you tell we're passing the tipping point on climate change? The climate rubes in Texas have been switching from eager denial to eager seekage of Federal dollars to offset the disaster they caused. Watch as they double up on last year's request for Federal aid. Watch as they duke it out for control of not-enough water.

Later this week I'll quote from Bill McKibben's piece on the same subject. McKibben has called it "the most important thing I've written in many years."

Now Hansen, truly one of the bigs in this field. His new paper begins (my emphasis and paragraphing throughout):
"Climate dice", describing the chance of unusually warm or cool seasons relative to climatology, have become progressively "loaded" in the past 30 years, coincident with rapid global warming.
Not just "global warming" — "rapid global warming." It's coming fast.

Let's pause. "Loaded dice" is not just a general metaphor. Hansen is saying something very specific.

The "chance of unusually warm or cool seasons relative to climatology" (i.e., climate norms) refers to the odds of swings, or deviations, from the norm.

In other words, it's not statistically significant that one summer is hot, another cooler, another very hot, and so on — as long as the swings don't stray too far from the norms in too many cases.

Once wide swings from the norm become regular, something else is going on — the "norms" are being redefined. His metaphor for that is unloaded dice versus loaded dice — dice with weights in them that force certain numbers to come up far more often that statistics would dictate.

Note: Not more often; far more often — often enough that crooked gamblers can count on making money on the weighted outcomes. In other words, there's now a new norm.

He continues, saying what I just said, but in math-prettier language:
The distribution of seasonal mean temperature anomalies has shifted toward higher temperatures and the range of anomalies has increased.

An important change is the emergence of a category of summertime extremely hot outliers, more than three standard deviations (σ) warmer than climatology. [See below for definition.]

This hot extreme, which covered much less than 1% of Earth's surface in the period of climatology, now typically covers about 10% of the land area.

We conclude that extreme heat waves, such as that in Texas and Oklahoma in 2011 and Moscow in 2010, were "caused" by global warming, because their likelihood was negligible prior to the recent rapid global warming. We discuss practical implications of this substantial, growing climate change.
That's his first paragraph, his "executive summary." (See why I break it out for you? It's a paper, not a blog post.)

By the way, a "standard deviation" is a statistical measure of how much the data normally varies over a period of time. Three standard deviations is a lot of variance from what would normally occur.

The rest of his piece supports his conclusion. He adds:
The greatest barrier to public recognition of human-made climate change is the natural variability of climate. How can a person discern long-term climate change, given the notorious variability of local weather and climate from day to day and year to year?

This question assumes great practical importance, because of the need for the public to appreciate the significance of human-made global warming.

Actions to stem emissions of the gases that cause global warming are unlikely to approach what is needed until the public perceives that human-made climate change is underway and will have unacceptable consequences if effective actions are not taken to slow the climate change.

Early recognition of climate change is critical. Stabilizing climate with conditions resembling those of the Holocene, the world in which civilization developed, can only be achieved if rapid reduction of fossil fuel emissions begins soon (1).
A perfectly reasonable problem — Assuming George "It's just summertime" Will is an honest questioner, how does one respond? Hansen's piece has the answer.

That takes you through his first three paragraphs. The rest is explanation and verification — the math et al. A great read, and not all that long (17 pp). I do recommend it.

For example, he talks about the importance of summertime, "the season when most biological productivity occurs." Hadn't thought of that, but it's true.

Then he lets loose with this whooper towards the end:
Although species migrate to stay within climate zones in which they can survive, continued climate shift at the rate of the past three decades is expected to take an enormous toll on planetary life. If global warming approaches 3°C by the end of the century, it is estimated that 21-52% of the species on Earth will be committed to extinction.
The piece is loaded with great charts (and fun statistics). I want to tease you with this graphic. Obviously the whole world isn't undergoing these anomalies, and the parts that are, are undergoing different anomalies than others.

But this caught my eye (ahem, Texas) from Fig 8 (click to big):

Fig. 8 (part). Jun-Jul-Aug and Dec-Jan-Feb temperature anomalies (°C) for area shown on the right.

Two standard deviations above the norm in 2011. And notice the trend; there's clearly more where that came from (and again, less water where that came from as well).

I'm willing to bet that the eagerly fooled in Texas (technical term: "Daddy-seeking climate rubes") will want us to pay for their mistake in following David Koch to the cleaners.

I'm also willing to let Texas secede ... retroactively. But maybe that's just me.


To follow or send links: @Gaius_Publius

blog comments powered by Disqus