We’ll have to wait and see.
The researchers assume that:
… ice growth mainly responds to insolation and CO2 forcing…
There is no scientific evidence that this assumption is correct.
The University of Florida media release is below.
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Global warming caused by greenhouse gases delays natural patterns of glaciation, researchers say
GAINESVILLE, Fla. — Unprecedented levels of greenhouse gases in the Earth’s atmosphere are disrupting normal patterns of glaciation, according to a study co-authored by a University of Florida researcher and published online Jan. 8 in Nature Geoscience.
The Earth’s current warm period that began about 11,000 years ago should give way to another ice age within about 1,500 years, according to accepted astronomical models. However, current levels of carbon dioxide are trapping too much heat in the atmosphere to allow the Earth to cool as it has in its prehistoric past in response to changes in Earth’s orbital pattern. The research team, a collaboration among University College London, University of Cambridge and UF, said their data indicate that the next ice age will likely be delayed by tens of thousands of years.
That may sound like good news, but it probably isn’t, said Jim Channell, distinguished professor of geology at UF and co-author.
“Ice sheets like those in western Antarctica are already destabilized by global warming,” said Channell. “When they eventually slough off and become a part of the ocean’s volume, it will have a dramatic effect on sea level.” Ice sheets will continue to melt until the next phase of cooling begins in earnest.
The study looks at the prehistoric climate-change drivers of the past to project the onset of the next ice age. Using astronomical models that show Earth’s orbital pattern with all of its fluctuations and wobbles over the last several million years, astronomers can calculate the amount of solar heat that has reached the Earth’s atmosphere during past glacial and interglacial periods.
“We know from past records that Earth’s orbital characteristics during our present interglacial period are a dead ringer for orbital characteristics in an interglacial period 780,000 years ago,” said Channell. The pattern suggests that our current period of warmth should be ending within about 1,500 years.
However, there is a much higher concentration of greenhouse gases trapping the sun’s heat in the Earth’s atmosphere now than there was in at least the last several million years, he said. So the cooling that would naturally occur due to changes in the Earth’s orbital characteristics are unable to turn the temperature tide.
Over the past million years, the Earth’s carbon dioxide levels, as recorded in ice core samples, have never reached more than 280 parts per million in the atmosphere. “We are now at 390 parts per million,” Channell said. The sudden spike has occurred in the last 150 years.
For millions of years, carbon dioxide levels have ebbed and flowed between ice ages. Orbital patterns initiate periods of warming that cause ocean circulation to change. The changes cause carbon dioxide-rich water in the deep ocean to well up toward the surface where the carbon dioxide is released as a gas back into the atmosphere. The increase in atmospheric carbon dioxide then drives further warming and eventually the orbital pattern shifts again and decreases the amount of solar heat that reaches the Earth.
“The problem is that now we have added to the total amount of CO2 cycling through the system by burning fossil fuels,” said Channell. “The cooling forces can’t keep up.”
Channell said that the study, funded by the National Science Foundation in the U.S, and the Research Council of Norway and the Natural Environment Research Council in the United Kingdom, brings to the forefront the importance of atmospheric carbon dioxide because it shows the dramatic effect that it is having on a natural cycle that has controlled our Earth’s climate for millions of years.
“We haven’t seen this high concentration of greenhouse gases in the atmosphere for several million years,” Channell said. “All bets are off.”
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Stated simply, the 90% of the ice below the water is less dense than water, so that 90% of the ice becomes denser when it melts, by the exact amount to make room for the 10%. Don’t you love science? Actually, all 100% becomes denser when it melts. Duh.
Check this out: http://ca.news.yahoo.com/forget-mayan-2012-prediction-expert-says-world-ends-091007928.html
500 million years, guys!
“We haven’t seen this high concentration of greenhouse gases in the atmosphere for several million years” – What the hell? Where has this guy been? Clearly he has not studied history whatsoever. During the age of the dinosaurs Co2 was at 7000ppm, way higher than it is now.
As for the Ice Age, it may come even sooner, since these ignorant scientists do not realize that greenhouse gases prevent glaciation. They are putting us on death row here. When they start finding that vegetation can no longer grow, they’ll blame it on Co2 and Global Warming…completely unaware that warmth and CO2 is the reason why they survive.
Tens of thousands of years? Last I heard it was 1500. Given the circumstances it may be sooner. This study will (hopefully) be torn apart and the researchers will run away with their tails between their legs. What they are doing is making scare claims based on faulty science. As you say, there is no evidence that proves any of their claims. A study based on faulty data is a faulty study. We should not take this study seriously.
@William Nuesslein – That 10% above the water level already exerts presure becuase of the weight, so melting will not cuase any change. You can do an experiment to prove this. Put a glass or container of water of your preference and place an ice or many on top. Make sure that the ice(s) are not touching the glass in 3 different spots. Sides and bottom. And that the ices are not mounted on each other. Also make sure that the water level is close to the top of the glass. Let it melt and see if the water spills out of the container.
Yes it would. The 10% above the water level would melt into the water.
If these ice sheets are over the water, then they have already displaced the sea water below them. Let them melt, the oceans will not rise one iota.
I live in Minnesota. Our winters qualify as ‘ice age’ to most other folks. I am not put out over a real ice age being delayed. Really. *grin*
I agree that we should be enviromental conscience, but focusing on what may happend in 20,000 years will not help todays pollution problems. We need to be responsibles at home, with energy consumption and with aquiring new tecnology to produce clean electricity.
Mt Pinatubo erupted in the Philippines in 1991, it spewed out more greenhouse gases into the atmosphere than the entire human race had emitted in all its years on earth. I’d say the delay of the next ice age theory is FAIL!
So what?
Low CO2 and Glaciation is not a normal climate state over the last 500 million years. Glaciation was present 300 million years ago, and for the last several million years. These periods of glaciation had low levels of CO2. The CO2 levels for the rest of the period were generally 1000 to 2000 PPM. The mid Eocene warm period reached higher levels.
“With a realistic range of phosphate concentrations, pCO2 values were between 600 and 1600 ppmv just before the MECO, which is in line with previous estimates of middle Eocene pCO2 values using the same proxy (14), and rose to between 6400 and 15,000 ppmv during the MECO” (Middle Eocene Climatic Optimum ) http://www.sciencemag.org/content/330/6005/819.full
The warming seen in the MECO with CO2 over 6400 PPM CO2 did not result in catastrophic environmental effects, This was the period of high mammalian speciation, not extinction. http://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Thermal_Maximum
If we are choosing between a mile of ice on New York, or trees on Baffin island, which would you choose?