Posted on 12/12/2006 8:13:39 AM PST by cogitator
The worrying shrinkage of Arctic sea ice could accelerate dramatically in coming decades, leaving the planet's most northerly ocean virtually devoid of ice in summer by 2040, according to a study published on Tuesday.
The paper, which appeared in the US journal Geophysical Research Letters, mainly points the finger at greenhouse-gas emissions.
It warned that if carbon pollution continues to increase at present rates, the Arctic's normal cycle of freezing and thawing faces catastrophic disruption.
A simulation run by scientists at the National Center for Atmospheric Research (NCAR) and Canada's McGill University predicted that the area covered by ice in September -- before new ice begins to form each year -- could shrink from about 5.9 million square kilometres to 1.9 million sq. kms. (2.3 million to 770,000 sq. miles) within a decade.
By 2040, "only a small amount of perennial sea ice" would remain along the north coasts of Greenland and Canada in summer, NCAR said in a press release.
In winter, ice thickness would be reduced from about 3.5 metres (about 12 feet) to less than a metre (three feet).
"We have already witnessed major losses in sea ice, but our research suggests that the decrease over the next few decades could be far more dramatic than anything that has happened so far," said NCAR scientist and lead author of the study, Marika Holland.
Greenhouse gases trap the Sun's heat, gradually forcing up Earth's surface temperature.
But several peripheral factors could also account for such a rapid meltdown.
Open water absorbs more sunlight than ice, accelerating the rate of warming and leading to more ice loss. In addition, global climate change is likely to drive warmer ocean currents into the Arctic region.
"This is a positive feedback loop with dramatic implications for the entire Arctic region," Holland said.
The shrinkage of the Arctic ice cap is viewed with alarm by scientists, as it appears to perturb important ocean currents elsewhere, notably the Gulf Stream, which gives western Europe its balmy climate.
It also threatens animals such as polar bears and seals that depend on ice -- as well as Inuits and other native peoples who hunt these animals and have to travel on thinner ice in this quest.
There are geopolitical implications, too, as Canada, Russia and the United States jockey to claim rights over transpolar passages that open up within their newly ice-free waters.
In September, European scientists unveiled satellite images from late August showing that perennial sea ice -- thick ice that is normally present year-round and is not affected by the Arctic summer -- had disappeared over an area bigger than the British Isles.
The study released Tuesday concludes that reduced rates of greenhouse gas emissions could slow the ice loss. "Our research indicates that society can still minimize the impacts on Artic ice," Holland said.
Cogitator:
The Vostok ice core data show that temperature increases occurred approximately 1,000 years before increases in CO2. Repeatedly, over several glaciations and deglaciations.
This suggests that rising CO2 is an effect, not a cause, of global warming.
How do you reconcile these data with the conjecture of anthopogenic global warming?
Ten years is so quick, why bother trying to stop this process. It seems a turnaround is too late and we need to figure adaptive strategies.
The climate experts were TOTALLY OFF in their predictions of Atlantic hurricane activity this year. Therefore, the onus is on environmentalists to get a few predictions right before we assign them any credibility.
As others have pointed out, most of these eggheads know they are safe because they make predictions so far out in the future it is difficult to check their work. What we do know is all the most publicized doom mongers of the 70s and 80s were NOT CREDIBLE.
You're welcome. :) bttt
The U. of Colo. also believes this report. And if Inhofe really uses sciresearch that is not based on models, yes, he and others will tell Gore, the McGillites, that proof is needed with more research than their computer models.
As a matter of certain fact, yes, they do consider that as a possibility. Cloud feedback effects are considered the top uncertainty in all GCMs. It is possible that cloud feedback effects could cancel out the effects of increasing CO2 in the atmosphere. It will be VERY interesting to see what the next IPCC report says about clouds.
Glacial/interglacial changes are primarily driven by Milankovitch cycle forcing. Milankovitch cycles change the total amount of solar insolation the Earth receives. When the cycles positively or negatively reinforce each other, there are significant maxima and minima in solar insolation. These maxima and minima mark the glacial/interglacial transitions. The changes driven by solar insolation are reinforced by a positive or negative global temperature feedback driven by atmospheric CO2 concentrations.
Now aren't you glad you asked? If you want to check and see if my basic description above is accurate, use Google.
The Antarctic is very isolated case.
As if there is any doubt. The IPCC will conclude that clouds will accelerate global warming. It is not a scinece, it is an agenda.
Since I used the term "qualitative", quantifying it would be a mistake. The IPCC Third Report said "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities." If most of the warming is attributable to human activities, then the human contribution is certainly not neglible, as I stated.
In many other FR discussions, I have pointed out that climate scientists have considered other climate forcing factors, such as solar activity and volcanoes, for the global climate since the mid-1850s. When you run the models using the known forcings from these, the models do not produce the observed warming. If anthropogenic CO2 is added, the models are close to the observed warming. If one asserts that anthropogenic CO2 is not to blame for the warming, then another "mytery" forcing of the same magnitude has to be found to replace it.
The emissions from Erebus do not affect stratospheric ozone. Since your posting tone was facetious, I hope that you already know this.
You shouldn't be dishonest when you characterize Inhofes views. He acknowledges that the Earth has been warming since the Little Ice Age which is a good thing both substantively and politically.
Inhofes problem is with the Globaloneyists.
No, they're not. While there are a few skeptical holdouts, the vast majority acknowledge the reality of anthropogenic climate change.
Simple, lagging CO2 concentrations are the leading edge of the next warming cycle. Fuzzy science.
Pure speculation. There is nothing that supports that.
Kind of convenient that the early industrial age did not contribute to global cooling in the 30's and 40's. Cherry-picking data, typical of IPCC tactics.
But how many buy into the catastrophic climate change predictions that appear daily in our newspapers and are posted by you?
Of course they do. The models were made to fit the observed warming with their assumed anthropogenic CO2 effects. So when you remove that component, it no longer matches. Using models that were fitted to the data do not prove anything. You could easily change the effects of other components to match the data also.
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