Impacts of Climate Change (Ecosystems)

Question 1

Present impact on tropical rainforests

Answer 1

Climate change is leading to increased temperatures and changing rain patterns; the Amazon Basin has seen 10-20% less rainfall. Forest fires are more common and extensive (seen with the Amazon fires of 2019). Species are being forced to cope with changing conditions with tree fruiting patterns changing (having knock-on effects in the food chain).

Question 2

Future impact on tropical rainforests

Answer 2

Rainforests are being pushed towards a tipping point after which 30-60% of the Amazon could become dry savanna. This change could change the Amazon from a carbon sink to a carbon source and create a positive feedback loop. Increased storm runoff in large rainfall events could endanger mangroves and fish with more intense flash flood events.

Question 3

Vulnerability of tropical rainforests

Answer 3

The IPCC predicts that tropical rainforests will be ‘significantly impacted’ by climate change. Growing human pressures from population growth, deforestation and increasing transport infrastructure further threatens the biome. The Amazon basin is the most vulnerable but rainforests in South China are also under stress (exacerbated by land-use changes).

Question 4

Present impact on coral reefs

Answer 4

500mn people are supported by coral reefs for food and jobs. Coral bleaching has already occurred as a result of the increase in global temperatures; carbon dioxide emissions have led to more carbon dioxide in the ocean creating very dilute carbonic acid which further bleaches the reefs. Sea level rise means that less light is reaching the coral stopping photosynthesis. Tropical storms becoming more intense further threatens coral reefs; Typhoon Mangkhut in 2018 destroyed 80% of coral reefs off the coast of Hong Kong.

Question 5

Future impact on coral reefs

Answer 5

As temperatures continue to rise, coral bleaching is predicted to get worse. Under the 2C target there could still be complete coral extinction as early as 2040. 70% decrease in pH below natural levels expected by 2100. All present problems will just continue to get worse with more sea level rise and more intense tropical storms.

Question 6

Vulnerability of coral reefs

Answer 6

Slight changes in pH, temperature or sea level is devastating for coral reefs as they are very fragile; algae on the reefs supply 90% of energy for the coral and without it, it cannot survive. This will have an impact on fish who reside in coral reefs. Under 2C rise, 99% of coral will die.

Question 7

Present impact on Arctic environments

Answer 7

The Arctic is warming three times as fast as the global average. Increasing temperatures have caused sea ice, permafrost, and glacial melt. This has created positive feedback loops as more carbon is released into the atmosphere; darker surfaces exposed from the melting of snow further speed up temperature rise due to the albedo effect. Melting of ice leads to the loss of habitats. Arctic tundra is generally greening which could act as a carbon sink (though likely not enough to counterbalance permafrost melt).

Question 8

Future impact on Arctic environments

Answer 8

As temperatures continue to rise, cryosphere melt will accelerate. This will contribute to rising sea levels with Greenland alone potentially raising sea levels by 14-33cm; global impact of Arctic environments. Permafrost thaw also releases methane (which is 25 times more potent). By 2100, polar bears could face starvation and reproductive failure.

Question 9

Vulnerability of Arctic environments

Answer 9

Arctic fauna are susceptible to climate change; loss of 30% of polar bears by 2050. Oil exploration in the Arctic sea could further accelerate the process. Global tree line rising will cause biome change in the Arctic tundra. Since 1970, the extent of Arctic sea ice has shrunk by