One shows a nonlinear transition to a new stable state in < 10 years
when polar temperature rises above − 5 °C (13 °C above present), whereas the other shows a more linear transition.
Not exact matches
But
when tree rings, pollen counts in
polar ice, and
temperature records from multiple places around the world all point in the same direction, we become increasingly confident that global warming is a reality.
Thus
temperatures during the period
when a lot of sunlight first returns to the
polar areas following winter, March in the Arctic and September in the Antarctic, are crucial.
When low -
temperature ice covers the Arctic Ocean there is little evaporation or sublimation and the
polar regions are quite dry in terms of precipitation, comparable to the amount found in mid-latitude deserts.
The
temperatures themselves are greatly influenced by the strength of the
polar vortex, a wind that swirls around the pole and
when strong, can keep air confined throughout the winter in the
polar night, allowing it to cool dramatically.
Thus
temperatures during the period
when a lot of sunlight first returns to the
polar areas following winter, March in the Arctic and September in the Antarctic, are crucial.
«Borehole
temperatures in the ice sheets spanning the last 6000 years show Antarctica repeatedly warming
when Greenland cooled, and vice versa... The phenomena has been called the
polar see - saw... Attempts to account for it have included the hypothesis of a south - flowing warm ocean current with a built in time lag... There is (however) no significant delay in the Anarctica climate anomaly...
Mid-latitude storms are most active during winter, i.e. cold season,
when the Arctic experiences
polar nights and there is stron
temperature gradients.
The corresponding future
temperatures in Greenland are comparable to those inferred for the last interglacial period 125,000 years ago,
when paleoclimatic information suggests reductions of
polar land ice extent and 4 to 6 m of sea level rise.
On the onset of spring,
when the Sun comes up over the
polar night but the air is still winter - cold, over the Arctic all conditions can suddenly be met to set the catalytic ozone breakdown reaction in motion: sunlight, moist, CFKs [yes, they're still around] and
temperatures of -90 ºC (or colder).
When talking about climate change, most of us imagine a smattering of statistics flowing across charts and figures showing rising
temperatures, the thawing of ice on mountain caps and
polar... Read more»
The northern latitude areas have benefited from rising
temperatures due to the «
polar amplification», but
when the process is reversed they may suffer the most.
Often
when the
polar vortex is strong,
temperatures are mild in the mid-latitudes across the Eastern US and Northern Eurasia; and
when the vortex is weak,
temperatures tend to be cold across the Eastern US and northern Europe and Asia.
Sudden Stratospheric Warming (SSW)-
when temperatures rise dramatically in the
polar stratosphere in a mater of days.
When oceans get cold, and the surface of
polar waters freezes, it snows much less and the sun takes away ice and limites the lower bound of
temperature and sea level.
The
temperature that
polar oceans thaw, Arctic and Antarctic, is the set point and cooling is always turned on
when the oceans thaw and cooling is always turned off
when the oceans freeze.
And we also don't get say 15 C increase in
temperature in Tropics
when it is a 30 C world, nor does the poles become much colder
when we in colder world of 10 C, rather it's expansion area of
polar region climate and contraction of tropical regions.
The high and persistent
temperatures this fall are particularly extraordinary, scientists said, because the region has already plunged into «
polar night,» the time of year
when the sun no longer rises over the North Pole.
The zone of convergence, or
polar front, is most strongly developed in winter,
when the contrast in
temperature and humidity of the air between the converging flows is greatest.
The last time in Earth history
when the global average surface
temperature was as warm as the IPCC projects for 2100 in its mid-range scenarios, there was very little
polar ice and sea level would have been roughly 70 meters (over 200 feet) higher than at present.
For example, Gavin's Pussycat has already pointed out that in their analysis they did not take into proper account how
polar amplification results in larger swings in
temperature at higher latitudes — and that
when estimating
temperature variation at lower latitudes on the basis of proxies at higher latitudes one has to scale down the variation, that is recognize that the swings in
temperature will be smaller at those lower latitudes.
The latitudinal
temperature gradient in summer is much smaller, thus providing less drive for exchange of air masses between middle latitudes and
polar regions — and
when exchange occurs the effect on
temperature is less than that caused by a winter «
polar express» of Arctic (or Antarctic) air delivered to middle latitudes.
«Stratospheric sudden warming» events occur
when temperatures rise and 80 - mph «
polar vortex» winds encircling the Artic suddenly weaken or even change direction.
To sum up, recent global
temperatures, weather,
polar ice and sea levels are consistent with our knowledge of corresponding Holocene climate variability measures
when man was not a factor to be considered.
It is also a significant place
when it comes to global climate change — it is the
polar regions of the planet that are experiencing the biggest rises in
temperature and changes to the landscape, threatening the very survival of the
polar bear.