With publication of a column in the NYTimes over the weekend, the "cantankerous" former skeptic on seriousness of climate change, physicist Richard Muller, announced his team at Berkeley Earth's latest findings.
Here's the central graph, correlating greenhouse gas emissions to the rise in temps:
"The historic temperature pattern we observed has abrupt dips that match the emissions of known explosive volcanic eruptions; the particulates from such events reflect sunlight, make for beautiful sunsets and cool the earth’s surface for a few years. There are small, rapid variations attributable to El Niño and other ocean currents such as the Gulf Stream; because of such oscillations, the “flattening” of the recent temperature rise that some people claim is not, in our view, statistically significant. What has caused the gradual but systematic rise of two and a half degrees? We tried fitting the shape to simple math functions (exponentials, polynomials), to solar activity and even to rising functions like world population. By far the best match was to the record of atmospheric carbon dioxide, measured from atmospheric samples and air trapped in polar ice."
"Just as important, our record is long enough that we could search for the fingerprint of solar variability, based on the historical record of sunspots. That fingerprint is absent. Although the I.P.C.C. allowed for the possibility that variations in sunlight could have ended the “Little Ice Age,” a period of cooling from the 14th century to about 1850, our data argues strongly that the temperature rise of the past 250 years cannot be attributed to solar changes. This conclusion is, in retrospect, not too surprising; we’ve learned from satellite measurements that solar activity changes the brightness of the sun very little."
"How definite is the attribution to humans? The carbon dioxide curve gives a better match than anything else we’ve tried. Its magnitude is consistent with the calculated greenhouse effect — extra warming from trapped heat radiation. These facts don’t prove causality and they shouldn’t end skepticism, but they raise the bar: to be considered seriously, an alternative explanation must match the data at least as well as carbon dioxide does. Adding methane, a second greenhouse gas, to our analysis doesn’t change the results. Moreover, our analysis does not depend on large, complex global climate models, the huge computer programs that are notorious for their hidden assumptions and adjustable parameters. Our result is based simply on the close agreement between the shape of the observed temperature rise and the known greenhouse gas increase."
The superb Knight-Ridder Science Journalism Tracker at MIT comments:
What stands out is that many major [media] outlets did not cover it. Perhaps they regarded this as politics, not science - paying big attention to Muller's turnabout may be like giving big headlines to the fourth-from-last finisher in a huge field of marathoners. Perhaps they are right.
Probably they didn't report it because the Berkeley Earth results haven't actually been peer-reviewed and published in a recognized journal. Though Muller is a well-known scientist who has won huge awards, he didn't wait for that process to go to completion, saying he didn't have time, and the press would report on the paper whether it was published or not. Hmmmm.
Create drama, then use said drama to get unreviewed results published in the press, against journalistic rules requiring peer-review first. Clever!
By sheerest of coincidences, his former supporter, prominent climate change denier, er, self-declared "lukewarmist" Anthony Watts, brings out a paper days later arguing (as Muller once did) that the temperature record is overstated, due mostly to the unaccounted-for influence of the urban heat island index on temperature stations. Ignoring the Berkeley Earth results, in other words. This earned him a lot of scorn from veteran scientist/bloggers such as William Connelley (aka Stoat) who called Watts a "drama queen" for heralding a paper before it's even been submitted for peer-review.
Connelley also pointed out that Watts previously refused to talk about the Muller/Berkeley Earth results because they hadn't been peer-reviewed. Now he wants the same coverage, w/ or w/o peer-review. Hypocrisy?
Or just practicality: If you can't beat 'em, join 'em?
Muller has dominated the coverage to date, as seen in the Los Angeles Times, which appears never to have heard of Watts.
Among scientists, Muller has received praise for his work from Michael Mann, famous for creating the so-called hockey stick. And he's' heard trash talk, also (in this case) from Mann:
At this rate, Muller should be caught up to the current state of climate science within a matter of just a few years!
It's true. Muller is late to the consensus, which is that we are are far up the creek, and not even -- so far -- looking for the paddle. That's why Watts' red herring matters -- because we still have a chance to make a difference, if we want to avoid a 7C rise by 2100, as seen in the chart below.
We're currently on the highest possible path -- A1F1, a "Business as Usual" scenario.