1.A.7 Changes in the carbon cycle

Physical factors affecting the carbon cycle

Geological timescale cycles, such as glacial or interglacial periods, or rock cycles

Volcanic activity, transferring carbon from the lithosphere to the atmosphere

Warmer periods and colder periods, change intake of carbon for oceans

Human factors affecting the carbon cycle

Hydrocarbon extraction and burning, transferring carbon from the lithosphere to atmosphere

Farming practises, livestock, ploughing and machinery all releasing carbon to the atmosphere

Deforestation and landuse changes - burning logs releases all the carbon stored in the wood

Wildfires as a transfer of carbon

Wildfires burn trees in a forest, but only release about 20% of the total carbon store in the forest to the atmosphere. Naturally, they make no net change in carbon, as the old trees burn so new trees can grow, which absorb the carbon that was released by the fire.

Human effects on wildfires

Humans are making wildfires greater and more frequent, either due to direct human engagement or climate change, which therefore does lead to a net release of carbon into the atmosphere

How many GtC do forests store globally

861 GtC

What is the trend inn CO2 released from wildfires since 1850

1850, rates increased because of industrialisation and deforestation as well as population growth, so more space needed for houses and food

1900s, rates plateaued, humans found a comfortable rate of emmissions, where we were living comfortably so didn’t need to cut down more than what we already were.

1970s, rates decrease, maybe because we are running out of trees to burn, or that the trees are younger and smaller so hold less carbon