Natural changes: Wildfires

Question 1

overview

Answer 1

This is a short term change. Wild fires can be started by lightning; however, increasingly they are started deliberately by people. Wild fires are restricted to small parts of the Earth’s surface but can have regional impacts.

Question 2

example

Answer 2

In 1997/98 and 2013 wild fires in Indonesia burned for months. Wild fires can take place in: boreal forests of Alaska, Canada and Russia, Savannah grasslands of Africa, Tropical forests in Brazil and Indonesia and Temperate forests in W. Europe.

Question 3

example

Answer 3

In 1997/98 and 2013 wild fires in Indonesia burned for months. Wild fires can take place in: boreal forests of Alaska, Canada and Russia, Savannah grasslands of Africa, Tropical forests in Brazil and Indonesia and Temperate forests in W. Europe.

Question 4

immediate impact

Answer 4

Fires release a large quantity of CO2 into the atmosphere causing a noticeable spike in carbon emissions. Wild fires can turn forests from being carbon sinks to carbon sources. Wild fires burn 3-4 million Km² of the Earth’s land surface area each year and release more than a billion tonnes of carbon into the atmosphere as CO2.

Question 5

longer term impact

Answer 5

In the longer term after the fire, new vegetation moves into the burned area and over time reabsorbs much of the CO2 that the fire released.

Combustion of vegetation and the loss of photosynthesising capacity result in higher CO2 levels in years of frequent wild fires. If a forest fully replaces itself, there will be no net carbon change over that life cycle which means they could have a neutral effect on the amount of carbon

Question 6

overall

Answer 6

Eventually, new trees grow, storing carbon and old trees decompose, emitting carbon and the organic layer of soil accumulates which is also a carbon store.