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Obo said that the increased ice has nothing to do with long term trends. Decreases do though?
The decrease in the Arctic does have to do with long term trends. The sea ice near Antarctica expands and shrinks seasonally. Currently it is expanding further than normal due to winds and melting of land ice.
The decrease in the Arctic does have to do with long term trends. The sea ice near Antarctica expands and shrinks seasonally. Currently it is expanding further than normal due to winds and melting of land ice.
Obo said that the increased ice has nothing to do with long term trends. Decreases do though?
The reason it's so easy for the deniers to persuade the ignorant is because this is too complicated for most people to actually understand, even though doing so really only requires a small degree of mental effort:
Is wintertime Antarctic sea ice increasing or decreasing?
Wintertime Antarctic sea ice is increasing at a small rate and with substantial natural year-to-year variability. Specifically, the months of May, June, July, September and October show trends of increasing sea ice extent that are just slightly above the mean year-to-year variability. In more technical terms, the trends are statistically significant at the 95% level, although small.
Climate model projections of Antarctic sea ice extent are in reasonable agreement with the observations to date. The dominant change in the climate pattern of Antarctica has been a gradual increase in the westerly circumpolar winds. Models suggest that both the loss of ozone (the ozone hole that occurs in September/October every year) and increases in greenhouse gases lead to an increase in this climate pattern.
When winds push on sea ice, they tend to move it in the direction they are blowing, but the Coriolis effect adds an apparent push to the left. In the unconfined system of Antarctic sea ice, this pushes the ice northward away from the continent. By spreading sea ice westward and a little northward (and since we measure extent with a 15% cut-off) the gradual trend towards faster mean winds means a gradual trend toward spreading of the ice cover.
Moreover, this trend towards stronger circumpolar winds appears to be causing the sea ice decline near the Antarctic Peninsula. In general the winds tend to dive slightly southward as they approach the Peninsula, an effect of the mountain ridges of the Andes and other circulation features in the Amundsen and Bellingshausen Sea. A stronger wind from the northwest brings warmer conditions and therefore less ice to the region. Lastly, the El Nino and La Nina cycle also appear to influence sea ice in the Pacific sector. El Nino patterns (a warm eastern tropical Pacific) are associated with warmer winds and less ice; the opposite is true for La Nina.
Even if wintertime Antarctic sea ice were to increase or decrease significantly in the future, it would not have a huge impact on the climate system. This is because during the Antarctic winter energy from the sun is at its weakest point; its ability or inability to reflect the sun’s energy back into space has little effect on regulating the planet’s temperature.
tl,dr:
Greenhouse gases in combination with the ozone hole and the Coriolis effect is creating winds that are spreading the sea ice out in the Antarctic, but this will have only a very limited effect on climate change because the energy from the sun during the Antarctic winter is at its lowest point and because the increase isn't enough to offset the large decrease in sea ice in the Arctic.
You don't want to reflect the heat away from the Earth when it's coolest, you want to do it when it's warmest... and it's their respective summers when almost ALL of the sea ice melts in Antarctica and depending on the weather, a great deal of it melts in the Arctic.
On top of this, Arctic sea ice is much thicker than Antarctic sea ice. Even if it is at its 'highest level', it doesn't mean that an increase in Antarctic sea ice is evidence that the Earth is cooling or that winter sea ice is going to lead to a cooler summer. It mostly means that the climate is more volatile overall in the Antarctic, with higher highs and lower lows.
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