Tag Archives: Intergovernmental Panel on Climate Change

A few answers regarding sea level rise

Because of the holidays, I did not get an immediate response from several climate experts I contacted following Nels Sultan’s comments about sea level rise in a blog post regarding “king tides.”

Earth at the winter solstice, Dec. 22, 2011 / NOAA photo

If you recall, Nels was making the point that the sea level in Seattle has been rising at a steady rate of .68 feet, or about 8 inches, per century since 1898, as reported by the National Oceanic and Atmospheric Administration.

His post included this statement:

“There is no real basis for the claims that sea levels will rise by 2.6 feet or 7 feet, or more. Globally, sea level rise has NOT accelerated. As found and reported by many researchers who specialize in this, including the eminent professor Bob Dean and other coastal experts.”

As a reporter, I’m not inclined to shoot back a response. I’d rather discuss the issue with experts in the field. That is what I did, and I think I have a better handle on the issue.

What I’m hearing is that the original estimates by the Intergovernmental Panel on Climate Change — a rise of between 7 inches and 2 feet by the end of the century — remain reasonable, but conservative given that they did not account for increased melting of the Greenland ice sheet. See this explanation by Stefan Rahmstorf soon after the release of the 2007 IPCC report. By the way, the range above accounts for the minimum and maximum across six climate-change scenarios.

Ever since, researchers have been trying to find ways to account for the melting of the Greenland ice sheet, but the uncertainties remain high. A widely cited paper by W.T. Pfeffer, J.T. Harper and S. O’Neel suggests that “most likely” starting point for further refinement is .8 meter, or 31 inches, of sea level rise by 2100.

In some ways, the authors of the Pfeffer paper were trying to limit some of the extremes being reported by others, so they concluded that sea level rise could not be more than 6 feet by 2100. Some folks have reported 6 feet as the top of the range, as unlikely as that extreme may be. Check out this explanation posed by Real Climate and this response by Pfeffer and his collaborators.

As for the Houston-Dean paper that Nels Sultan mentioned, those authors created “various problems” in their assumptions, according to Eric Steig, professor of Earth and Space Sciences at the University of Washington. One major problem was the starting date of 1930, as explained by Stefan Rahmstorf in Real Climate:

“Other start dates either before or after this minimum show positive acceleration. Picking 1930 for this analysis is thus a classic cherry-pick, and according to the authors that is no accident. They write in the paper: ‘Since the worldwide data of Church and White (2006)…appear to have a linear rise since around 1930, we analyzed the period 1930 to 2010.’ The interval was thus hand-picked to show a linear rise rather than acceleration.

“Houston & Dean use their result to question the future acceleration of sea level rise predicted by Vermeer & Rahmstorf (2009) for the 21st Century as a consequence of global warming. They argue that the 1930s acceleration minimum calls into question the semi-empirical link between global temperature and global sea level proposed by us in that paper. However, it is clear they never bothered to check this, because quite the opposite is the case: our semi-empirical formula predicts this acceleration minimum, as the graph above shows. As it turns out, this is an expected outcome of the mid-20th-Century plateau in global temperature.”

I also discussed this issue of sea level rise with Lara Whitely Binder, outreach specialist for the UW’s Climate Impacts Group. While sea level rise means one thing on the world scale, she told me, the local impacts can be quite different.

If you live in Neah Bay on the Olympic Peninsula, for example, you are not likely to see any sea level rise until at least 2080. That’s because the entire land mass is uplifting as a result of movement along the tectonic plates, and the uplift is predicted to be faster than sea level rise until late in the century.

On the other hand, Central and South Puget Sound may not be uplifting at all and could be sinking, which would intensify the effects of sea level rise. Areas built on fill, including portions of Olympia, also could be sinking as the fill settles, Lara said.

In addition to global rise in sea level and local tectonic shifts, factors affecting regional sea level rise include thermal expansion of ocean waters and changes in onshore and offshore wind patterns.

During El Niño events, sea level can rise as much as 12 inches for several months at a time. The Climate Impacts Group analyzed more than 30 scenarios from global climate models and concluded that the change in wind patterns as a result of climate change could decrease sea level by as much as 1 inch or possibly increase it by as much as 6 inches. Review the white paper “Sea Level Rise in the Coastal Waters of Washington State” (PDF 2.4 mb) for more details.

How much an individual property is affected by sea level rise depends on the slope of the beach. Given the same rate of rise, water will affect a house sooner when it is built on a gradually sloping beach as opposed to a steep slope. In any case, tides and weather will always play a major role in water levels.

Lara told me that a group of West Coast researchers is working on a new report about sea level for publication later this year by the National Academy of Sciences. I’ll try to review that paper when it comes out.

I wish to thank Eric Steig, Lara Whitely Binder, Cliff Mass, David Montgomery and Nate Mantua for responding to my inquiry.

Rising global temperatures portend uncertain future

Global temperatures continue on a rising trend, according to scientists at NOAA’s National Climatic Data Center in Asheville, N.C. The implications of this trend are quite serious, and I’ll discuss some new studies after reviewing the temperature data for 2010.

The worldwide average surface temperature for the past year tied with 2005 as the warmest year on record, a record that goes back to 1880. And the year 2010 was the 34th consecutive year in which temperatures were above the 20th century average, according to a preliminary analysis by NCDC.

The decade of 2001–2010 was the warmest ever recorded for the surface of the Earth during that 130-year time period. It was some 1.01 degree F. above the 20th century average. The previous record for a full decade was also recent, 1991-2000, when the temperature was .65 degrees F. above the average.
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Guardian report examines ‘Climategate’

I hate to say it, but on rare occasions it is difficult to figure out where science ends and politics begins. I have always believed there is a clear distinction between scientific findings and public policy. But a few members of the Intergovernmental Panel on Climate Change blurred the line, whether we like it or not.

I just finished reading a 12-part series about Climategate published in The Guardian, a British publication. The series includes annotated comments written by those close to the issue.

If you care about climate change, you probably should pay attention to politics surrounding this issue. That means you probably should know about the controversy surrounding the stolen e-mails of a few key climate scientists.

This series, by reporter Fred Pearce, offers context that one cannot get by reading the e-mails alone. I was impressed by the balance that Pearce brings to the issue, neither defending nor attacking the scientists for their apparent failings. But he does comment on the personalities of the scientists as well as the skeptics who constantly stirred the pot.
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Brouhaha develops over climate change; so what’s new?


Sir Muir Russell, principal and vice-chancellor of the University of Glasgow from 2003 to 2009, was appointed by the University of East Anglia to head up a review of allegations against the Climate Research Unit.

The review will look at the stolen e-mails for evidence of data manipulation or suppression, review CRU’s overall data-handling policies, and investigate compliance with disclosure laws. Review is designed to determine whether activities were at odds with acceptable scientific practices.

The university has asked that the review be completed by spring, 2010.


Phil Jones has stepped aside as director of the Climatic Research Unit pending completion of an independent review of allegations involving e-mail hacked from the server of the University of East Anglia in England. Details of the investigation will be announced within days. See news release from East Anglia.

Prospects appear to be fading for any meaningful international agreements for addressing climate change, as originally planned for a conference in Copenhagen next month.

Meanwhile, climatologists and those familiar with recent studies continue to warn us that, if anything, early climate models were too conservative in their predictions of climate change. The longer we wait to take action, the harder it will be to slow the rate of warming. Plants and animals (including humans) will have a harder time adapting to new conditions. Some populations, possibly entire species, may have no place to go as they attempt to adapt or face extinction.

I tend to take such warnings seriously, although I am not oblivious to the many skeptics on this topic. In fact, in my search for understanding, I’ve read more than my share of blogs written by folks who either don’t believe the planet is warming or else don’t believe man has anything to do with it.

This morning, I participated in a national telephone conference with three climate experts: Richard Somerville, coordinating lead author of the last report by the Intergovernmental Panel on Climate Change (IPCC); Eric Steig, professor of earth and space sciences at the University of Washington; and Michael Mann, professor of meteorology at Penn State University.

They answered a variety of questions — ranging from new climate data to the implications of more than 1,500 “stolen” e-mails that have revealed the hidden, personal side of a few climatologists.
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