[UPDATE Aug 24-28: The previous record low for daily Arctic sea ice extent was 4.16 million sq km, set on September 14, 2007. The new record was first set on August 24, 2012 and now stands at 3.85 million sq km. Sea ice extent was reduced by more than 430,000 sq km in five days (Aug 23-27), the most rapid late August loss on record. Click on thumbnail at right for latest Arctic sea ice extent as of today (based on latest NSIDC daily data).
- Aug 22: 4.29 million sq km
- Aug 23: 4.19 million sq km
- Aug 24: 4.09 million sq km ***
- Aug 25: 3.97 million sq km
- Aug 26: 3.94 million sq km
- Aug 27: 3.85 million sq km
*** New record low for daily Arctic sea ice extent set on Aug 24.]
This year’s arctic ice melt season is generating extraordinary interest. 2012’s apparent descent toward a new record low in extent and area is dramatic enough, but it also comes as new analysis shows that summer sea ice loss is 50% more than previously thought in terms of volume, according to preliminary satellite data from CyroSat 2. Virtually ice-free summers in the arctic sea could well arrive by 2030, with troubling implications for accelerated albedo feedback and possibly disruptive changes in the jet stream.
A new record low, eclipsing 2007, does seem increasingly inevitable with each passing week. National Snow and Ice data Center data showed Arctic sea ice extent at 4.29 million square km yesterday, just under 2007’s September average, and a level only reached on September 7 back then. To be sure, 2012 is starting to bottom out, but most years have seen a similar pattern around now.
Here’s a snapshot of the 2012 melt season (with the small crosses denoting recent daily values), compared to the previous five years.
Just how low could 2012 go?
[UPDATE 08/17: In comments, Berkeley Earth team member Zeke Hausfather reveals that most of the discrepancy between the Berkeley Earth 2011 and 2012 results is due to a previously unreported error in latitudinal weighting in the earlier version.
UPDATE 08/20: The 2012 GHCN-only series has been uploaded by Zeke Hausfather. Also, I have added clarifications concerning absolute temperature uncertainty and data availability. The summary has been updated accordingly.]
The recent Berkeley Earth land-surface average temperature series is based on a greatly expanded database of station temperature data, along with a completely automated statistical averaging process. In contrast, established average temperature series from NOAA, NASA and HadCrut are based primarily on the smaller Global Historical Climate Network (GHCN) database, and use empirically derived homogenization methods to remove known biases, albeit supplemented by pure statistical methods.
Here, the post-1950 Berkeley Earth “complete” land series is compared to the preliminary Berkeley series released in 2011, as well as to GHCN-only simulated series, based on overall attributes of those unreleased series provided in the Berkeley Earth companion “methods” paper. The 2011 and 2012 “full” (ALL) series Berkeley versions both fall squarely in the range of the latest comparable series from the three other groups post-1950. However, the two Berkeley ALL series diverge over the 1980-2010 period, and lie completely outside each others’ 95% confidence intervals in the 2000s, when baselined to 1950-1979. This turns out to be due to a significant error in latitudinal weighting in the 2011 ALL series; the error was not publicly disclosed at the time of correction. The GHCN 2012 series falls halfway between the 2012 ALL and 2011 ALL series in the 2000s; 2012 GHCN and 2012 ALL each appear to diverge outside the other’s confidence interval in the 2000s. As well, there is an increasing widening between the 2012 GHCN and ALL series the further one goes back before the 1950-1979 baseline period, with the ALL series about 0.3 C cooler in the early 1800s.
Other issues requiring further analysis are also identified, particularly a reported reversal in the long-term trend of narrowing diurnal temperature range starting in 1987, which contradicts previous GHCN-based analyses.Taken together, these issues cast doubt on the robustness of the present Berkeley Earth analysis, and point up the need for more open data access and improved diagnostics in order to further assess the reliability of the Berkeley Earth approach to surface temperature analysis.
This month we kick things off with the renewed attacks on Tides Canada by oilsands booster (and Canadian Conservative government surrogate) Ethical Oil [h/t Holly Stick].
Meanwhile, Canadian environment minister Peter Kent is touting an improved outlook for meeting Canada’s 2020 goal for GHG reduction, even though any progress is more due to luck, accounting changes and strong action by some provincial governments, rather than any concrete action by the federal government. Not to mention that current projections for 2020 still leave Canada only 3% under 2005 levels, 19% above the promised target. I’m working on a couple of related posts, but they may take a little time yet.
The latest release from the Berkeley Earth team has unleashed a major kerfuffle in the blogosphere, out of all proportion with its scientific import. (By the way, I have a post on Berkeley Earth coming very soon, looking at some curiosities in the various Berkeley results).
Getting back to the science, arctic sea ice continues to melt at an extraordinary pace, and may well set a new record low this September.
The saga of statistician turned climate science critic Edward Wegman and his protege Yasmin Said has taken yet another strange turn. The pair’s tenure as editors-in-chief at the Wiley journal they founded three years ago quietly came to an unceremonious end recently, while release of the hard-cover encyclopedia based on the journal also appears to have been delayed. Not only that, but it now seems that Yasmin Said’s stint as research assistant professor at George Mason University ended at the same time.
Can Enbridge be trusted to build and operate the Northern Gateway oil sands pipeline in a safe and sustainable manner? Judging from today’s scathing National Transportation Safety Board report on Enbridge’s horrendous pipeline spill in Michigan two years ago, the answer would appear to be a resounding “No”! But that’s just one of the difficult questions faced by Enbridge today.
Some topics of possible interest:
Fueled by the record high heat, this [derscho] was one of the most powerful of this type of storm in the region in recent history, said research meteorologist Harold Brooks of the National Severe Storm Laboratory [website] in Norman, Okla. Scientists expect “non-tornadic wind events” like this one and other thunderstorms to increase with climate change because of the heat and instability, he said.
[Also see this climate scientist roundup: Is it now possible to blame extreme weather on global warming? by Leo Hickman of the Guardian. And Snapple weighs in with Will Attorney General Ken Cuccinelli Learn Anything from the Super Derecho Event of June 29, 2012? ]
The NOAA’s National Climate Data Center recently announced that the last 12 months were the warmest on record in the “contiguous” U.S., extending the 2011-12 hot streak that has now eclipsed the previous record in 1999-2000 by a half degree Fahrenheit. Apparently, that was just too much for the Heartland Institute’s James Taylor who used his regular column in Forbes magazine to accuse the NOAA of “doctoring real-world temperature data”. According to Taylor, the “alarmists” at NOAA “simply erase the actual readings and substitute their own desired readings in their place”.
But it turns out that Taylor’s source is none other than hapless climate blogger Steven Goddard, who recently leveled incoherent and unsupported false accusations against James Hansen and NASA’s Gistemp record, as well as NOAA. Goddard also relies on the same reviled NOAA data in his botched attempt to buttress his case that NASA is “hiding” an 80 year cooling trend. Never mind that the U.S. “lower 48” represents less than 2% of the Earth’s surface area in any event, or that past attempts to show U.S. cooling have been proven utterly wrong.
If Forbes has a shred of integrity, this sorry episode will surely result in an abject retraction and apology to NOAA, along with the banishment of Heartland from the magazine’s pages. And it’s also high time reputable commentators in the mainstream media called out the irresponsible behaviour of Forbes and other right-wing media.