Lecture 20 Climate Change

Question 1

how warming causes warming (Snow Cover)

Answer 1

Because of the albedo effect, most of the solar radiation that hits the arctic is reflected back into the atmosphere. As the earth is warming, more snow has been melting = less energy getting reflected = more getting absorbed = warmer soil = more melting = even less energy is getting reflected and so on.

In addition to this, roads and human activity has removed even more snow

Question 2

how warming causes warming (permafrost)

Answer 2

*Tundra soils contain TWICE as much carbon as the entire atmosphere. But 5-15% of the permafrost
carbon is vulnerable to melt and release by 2100!
*Permafrost inhibits decomposition and keeps the carbon locked away
*Warmer temperatures melt the permafrost and allow decomposition
*This releases CO2 into the atmosphere
*This could increase atmospheric CO2 across the planet and further increase warming

Question 3

how warming causes warming (Sea Ice)

Answer 3

*Warming = Ice has less time to thicken before the melt season starts
* leads to a thinner ice cover that is more prone to melting out in summer.
*sea-ice loss amplifies warming
*negative feedback loop from declining surface albedo

Question 4

Lake Stratification (4)

Answer 4

Taiga lakes are thermally stratified in summer and winter, but mix in spring and fall – dimictic.

This means that in the winter the top layer of water is 1c and the bottom layer is 4c and in the winter the top layer is 20c and the bottom is 4c

The boarder of these to temps is called the thermocline

increased temperatures can cause Summer stratification

Question 5

Climate change effect on lake stratification