lightblueline

The Worldwatch Institute posted an essay from James Hansen on the 20th anniversary of his first testimony to congress. It's worth a read (excerpts below):

James Hansen, June 23, 2008

Tipping Points Near

Today, I will testify to Congress about global warming, 20 years after my June 23, 1988 testimony, which alerted the public that global warming was under way. There are striking similarities between then and now, but one big difference.

Scientific uncertainty over the speed at which the Polar ice caps can/will melt is another feature of the current state of the science for climatologists. To melt ice actually takes energy, and the simple (drip-drip-drip) melting of an ice sheet the size of Greenland would take several hundred years. There is certainty in that simple model for Greenland's future. This is one reason why it was allowed into the recent IPCC report.

Climate Change Corp., August 16, 2007: John Shephard
[Professor John Shepherd FRS conducts research at the National Oceanography Centre, University of Southampton, UK, and is deputy director of the Tyndall Centre for climate change research]

Is the IPCC report too optimistic? Prof. Shephard reports on the work of James Hansen. You can read the whole report here:
Sea special report: NASA's James Hansen on the IPCC forecas

The article is also available below:

The Daily Mail (June 20, 2007) reports on a research article published in the Philosophical Transactions of the Royal Society A:

"A group of US scientists may have given the clearest warning yet that global warming is presenting an imminent threat to civilisation.

In an article published in Environmental Research Letters on May 24, 2007, James Hansen, NASA scientist, discusses the non-linearity of shelf ice melting and the reticence of scientists to announce their fears about this process. The whole article is worth a read. Below is just the section on sea-level rise risks:

The Manchester Guardian (April 23,2007) reviewed the Book, Six Degrees: Our Future on a Hotter Planet, by Mark Lynas. The book notes how various potential futures (based on the number of degrees the planetary climate warms) will impact human existence. From one to six degrees, which is the range envisioned by the recent IPCC report, the impacts grow almost exponential severe.
Here is an excerpt from this book review.:

The Ventura County Star (February 8, 2007) covered James Hansen's UCSB talk with an eye to it's own local vulnerability to sea-level rise:

"Much of Hansen's presentation was old news to those who've been following the science and politics of climate change over the past decade. And to those without some grounding in the subject, the very technical material probably was just baffling. But he did make a couple of points about the latest IPCC findings that were largely overlooked or incompletely explained in last week's media coverage of the report. And the most significant of these relates to sea level rise — a subject of particular interest in low-lying coastal regions such as western Ventura County.

SB Independent reporter and photographer Nick Welsh and Paul Wellman cover the local events surrounding the talk by James Hansen at UC Santa Barbara. The story involves several issues that are worthwhile examining, including the IPCC report and new scientific data and thinking on the non-linear process of the large ice sheets (Greenland and the West Antarctic) melting over the next hundred to a thousand years.

Nick still calls this the "Global Warming Debate," although IPCC may have just taken the "Debate" out of the picture. Like the "Earth Rotates Around the Sun Debate," after a while even the fringe groups and the media get the concept.

What we do have is an "Ice Melt Science" debate, which is centered on the lack of scientific models that can predict how large ice sheets actually melt, and what happens when they start to melt. The other question is this: can we afford to wait for the scientists to agree on everything before we start working to keep the water as ice on Greenland and off our beaches, freeways, and airport.

Hansen clearly thinks we do not have the luxury of certainty, given the potential danger of these ice sheets melting more rapidly than we have previously considered.

Lightblueline uses Greenland as the basis for its seven meter (actually 23 feet... not 21 feet) contour line. We do this for simplicity: Greenland is our symbolic climate change poster child. The lightblueline public awareness art project is not predicting when Greenland would melt, or even if Greenland would be the first ice sheet to melt: some scientists are more concerned about the West Antarctic ice sheet which holds 6 meters of sea-level rise water.

You can read the entire Independent story here:

The Scariest Man on the Planet

As Santa Barbara prepares to welcome James Hansen on February 5, we can read an interview he did which aired on February 2 on the program Living on Earth.

Dr. Hansen describes the scenario where ice sheet melting in the past resulted in a sea level rise at the rate of one meter every twenty years. When lightblueline talks about the vulnerability that climate change brings to coastal cities, this type of nonlinear process is precisely the target of our action. We are not predicting a seven meter rise in a century, even though this has happened in the past. We are predicting that the "business as usual" scenario of carbon generation will result in a global climate where we cannot be certain that the polar ice sheets will remain intact over the next several hundred years. The vulnerability to sea level rise is the same whether it takes seven decades or seventeen decades. We share a common future in Santa Barbrara that our children's children will face. We have only a few years to turn the situation around.