Peak Oil News and Message Boards

Subjectivist wrote:

dissident wrote:
I have made the point several times on this board before: comparing the climate sensitivity to CO2 increases today and 5.3 million years ago is not appropriate. We slipped into an ice age because the Panama channel closed and due to ocean currents around Indonesia about 5 million years ago and not because the CO2 was removed by some unknown process. So 450 ppmv CO2 today will have a different impact than it did 5 or 10 million years ago. From the paleclimate record there will be a smaller temperature response with today's sensitivity.

Really? How much smaller do you believe the response will be? So far from the effects we see in the Arctic the amplification has been higher than what the climate models were predicting, not smaller.

dissident wrote:

Subjectivist wrote:

dissident wrote:
I have made the point several times on this board before: comparing the climate sensitivity to CO2 increases today and 5.3 million years ago is not appropriate. We slipped into an ice age because the Panama channel closed and due to ocean currents around Indonesia about 5 million years ago and not because the CO2 was removed by some unknown process. So 450 ppmv CO2 today will have a different impact than it did 5 or 10 million years ago. From the paleclimate record there will be a smaller temperature response with today's sensitivity.

Really? How much smaller do you believe the response will be? So far from the effects we see in the Arctic the amplification has been higher than what the climate models were predicting, not smaller.

This smells of trolling. Which climate models? Please provide some references.

Everyone and his dog knows that climate GCM land and sea ice schemes are very primitive (glorified ice cube models). They also only started using coupled ocean-atmosphere models very recently (not for the previous IPCC round) due to lack of computer power. I have not seen the diagnostics of these coupled models. If they have realistic sea ice schemes (e.g. ones where the sea ice is transported by the ocean circulation as affected by the atmospheric circulation), then they should do a much better job of capturing the albedo loss we have seen during the last 10 years.

You show the basic problem with climate science: everyone thinks he's an expert. Do you have a gut feeling about the ocean circulation under different land mass arrangements? Do you also have a gut feeling about CO2 flux at the ocean surface due to different circulation regimes?

PenultimateManStanding wrote:Here's a good summary of the situation:

By the turn of the new millenium, finally the idea of abrupt change had reached some kind of critical mass among climate scientists. In a coming of age for the science, the National Research Council appointed a special committee to conduct a comprehensive review of the subject. Some of the brightest climate scientists in the business were asked to identify "critical knowledge gaps" and to recommend a research strategy. In 2002, the NRC committee issued its report Abrupt Climate Change: Inevitable Surprises.
"We do not yet understand abrupt climate changes well enough to predict them," Richard Alley, who chaired the NRC committee, wrote in a preface to the report. "The models used to project future climate changes and their impacts are not especially good at simulating the size, speed, and extent of the past changes, casting uncertainties on assessments of potential future changes. Thus, it is likely that climate suprises await us."
A problem that Alley and other paleoclimate scientists refer to as the "insensitivity of models" or the "model-data gap" sounds like a technical issue but really is more fundamental. It means that the models are unable to reproduce accurately the numerous epidodes of abrupt change that show up clearly in many environmental archives around the world. The reasons for this failure are not yet known, but the implications are plain enough. Until these highly sophisiticated numerical representations of Earth's climate system - running on the world's most powerful computers - are able to get the past right, what reason is there to believe they can get the future right?

Climate Crash, John D. Cox

The rapid melting of Greenland glaciers is captured in the documentary "Chasing Ice." The retreat of the ice edge from one year to the next sends more water into the sea. Now University of Washington atmospheric scientists have estimated that up to half of the recent warming in Greenland and surrounding areas may be due to climate variations that originate in the tropical Pacific and are not connected with the overall warming of the planet. Still, at least half the warming remains attributable to global warming caused by rising carbon dioxide emissions. The paper is published May 8 in Nature.

Subjectivist wrote:In case you missed it, last week Greenlands government opened up a vast new tract of oil leases off of their coastline.

Rising temperatures and ash from Northern Hemisphere forest fires combined to cause large-scale surface melting of the Greenland ice sheet in 1889 and 2012, contradicting conventional thinking that the melt events were driven by warming alone, a Dartmouth College-led study finds.

The findings suggest that continued climate change will result in nearly annual widespread melting of the ice sheet's surface by the year 2100, and that a positive feedback mechanism may be set in motion. Melting in the dry snow region does not contribute to sea level rise; instead, the meltwater percolates into the snowpack and refreezes, causing lower albedo and leaving the ice sheet surface even more susceptible to future melting. Albedo is the surface's ability to reflect sunlight.

The study appears in the Proceedings of the National Academy of Sciences. The study was conducted by the Thayer School of Engineering at Dartmouth and the Desert Research Institute. The research was supported by the National Science Foundation and NASA.

Greenland's icy reaches are far more vulnerable to warm ocean waters from climate change than had been thought, according to new research by UC Irvine and NASA glaciologists. The work, published today in Nature Geoscience, shows previously uncharted deep valleys stretching for dozens of miles under the Greenland Ice Sheet.

The bedrock canyons sit well below sea level, meaning that as subtropical Atlantic waters hit the fronts of hundreds of glaciers, those edges will erode much further than had been assumed and release far greater amounts of water.

Ice melt from the subcontinent has already accelerated as warmer marine currents have migrated north, but older models predicted that once higher ground was reached in a few years, the ocean-induced melting would halt. Greenland's frozen mass would stop shrinking, and its effect on higher sea waters would be curtailed.

"That turns out to be incorrect. The glaciers of Greenland are likely to retreat faster and farther inland than anticipated – and for much longer – according to this very different topography we've discovered beneath the ice," said lead author Mathieu Morlighem, a UCI associate project scientist. "This has major implications, because the glacier melt will contribute much more to rising seas around the globe."

lorenzo wrote: It's ours![We need preemptive propaganda more than ever now. Yankee: putting Walmarts on Antarctica first will not make it yours.]

Graeme wrote:Greenland will be far greater contributor to sea rise than expected

Greenland's icy reaches are far more vulnerable to warm ocean waters from climate change than had been thought, according to new research by UC Irvine and NASA glaciologists.

"The glaciers of Greenland are likely to retreat faster and farther inland than anticipated – and for much longer – according to this very different topography we've discovered beneath the ice," said lead author Mathieu Morlighem, a UCI associate project scientist. "This has major implications, because the glacier melt will contribute much more to rising seas around the globe."

phys.org

The IPCC was way too conservative....sea level rise is happening significantly faster then they predicted.

rockdoc123 wrote:

The IPCC was way too conservative....sea level rise is happening significantly faster then they predicted.

Hardly. IPCC AR5 indicated that the average rate for 1993 – 2010 was 3.2 mm/y with a range of 2.8 to 3.6 mm/yr.

Don't you know anything? Why do I have to explain the most simple things to you?

The IPCC AR5 report is the fifth and most recent IPCC report---it was published in 2013-2014. OF COURSE an IPCC report published in 2013 gets the rate of level rise right for the years 1993-2010----. BY 2013 the years from 1993-2010 are already in the past so the bit you quote isn't a prediction at all.

I suggest you look up the meaning of the word "prediction" before you make this boneheaded mistake agai