1.5 - Burning Problems

Question 1

How We Know About Past Carbon

Answer 1

Ice Cores - Can help determine levels of CO2, they also hold ash from volcanoes.
Tree Rings - The greater the thickness of tree rings, the better growing periods and higher temperatures.
Fossil Records - Fossils from animals which no longer in a certain area can suggest high/lower temperatures.
U-Shaped Valleys - Evidence of previous glaciation
Historical Sources - Paintings and diary entries tell us about climate events.

Question 2

Siberia Permafrost

Answer 2

Thawing starts after global temperature.
Globally, permafrost contains 1700bn tons of organic matter.
Carbon is sequestered and there is 4x that released into the atmosphere.

Question 3

Feedback Cycles

Answer 3

Something that speeds up or slows down a warming trend.

Question 4

Solar Radiation Pathways

Answer 4

31% reflected by clouds, 69% absorbed. Increased vegetation means darker surfaces and more solar absorption but also increased clouds meaning increased reflection.

Question 5

Natural Carbon Release

Answer 5

Cooler summers, so carbon cycle slows but warmer summers means increased phytoplankton growth and photosynthesis rates which increases CO2 sequestration.

Question 6

Negative Feedback Cycles (Himalayas)

Answer 6

Tree leaf fossils in the Arctic, suggesting plants and animals had to migrate towards the poles due to increased temperatures. But tectonics caused growth of mountains, making weathering faster. This solution then goes to the sea where it’s absorbed by phytoplankton, which die and sink, locking carbon away in the rock store. Carbon sequestration cools the planet.

Question 7

Positive Feedback Cycles

Answer 7

Hidden in the permafrost is methane, which is a more powerful GHG than CO2. If the permafrost melts due to global warming bare methane is released. The permafrost contains an organic pool of carbon in the form of dead plant matter. Organsims eat the dead plant matter and burp out methane, this then bubbles up from lake sediments and gets trapped in the ice, in the form of bubbles. Therefore when the ice thaws methane will be release which will release streams of gas. The methane heats the atmosphere, causing this to repeat.