Our World - first semester

revision for multiple choice exam in jan.

Land vs ocean - primary production (in %)

Land- 54%, Ocean - 46%. Roughly equal

what are the three main biological/chemical processes at play in terrestrial carbon cycle?

Photosynthesis

Respiration

Combustion

What anthropogenic activities effect the carbon cycle?

Burning of fossil fuels

Land use change (i.e. cultivation etc.)

Biomass burning

Forest regrowth + fire management

What ‘pump’ is most important in oceanic side of carbon cycle?

Solubility pump

What % carbon uptake in atmosphere vs. ocean vs. land

Atmosphere - 50%

Ocean - 29%

Land - 21%

(as of 2025) - point is, roughly 50/25/25

What causes most of the inter annual variability in co2 atmospheric concentration?

Land sink - photosynthesis variation across the seasons

What is the most variable of the carbon sinks?

Land - most biomass is on land

Ocean is not as variable, fairly constant

Where in ocean is it a co2 source?

Around the equator, but ocean is still a net sink

What % did climate change reduce carbon sinks by in 2015-24?

Land - 25%

Ocean - 7%

What sink are scientists most uncertain about in the future?

Land

What do ecologists define as pre-industrial?

1850-1900

Describe contradiction between co2 concentration and climate change on effects on carbon sinks

co2 concentration - can increase productivity, fertilises photosynthesis

climate change - increased warming can reduce the capacity of sinks to take in excess co2