Water and climate regulation
Big idea: Water is Earth's thermostat. It absorbs, stores, and redistributes heat around the planet, keeping temperatures stable enough for life.
How water regulates temperature
- High specific heat capacity — water absorbs large amounts of heat with only a small temperature change (oceans act as heat sinks)
- Latent heat — evaporation absorbs heat (cooling), condensation releases heat (warming)
- Ocean currents — redistribute heat from the equator to the poles (e.g., the Gulf Stream warms western Europe)
- Water vapour as a greenhouse gas — traps heat in the atmosphere (can act as a positive feedback during warming)
- Albedo — ice/snow reflect sunlight (cooling), open water absorbs sunlight (warming)
For outline-style answers, give several distinct points (one per sentence), such as: high specific heat capacity, latent heat transfer, ocean currents, water vapour as a greenhouse gas, and albedo effects from ice/snow.
Water and the carbon cycle connection
Oceans also regulate climate by acting as carbon sinks. They absorb about 25% of human CO2 emissions, but this contributes to ocean acidification (see 4.4).
Water regulates climate through: (1) absorbing heat, (2) transporting heat via currents, (3) transferring heat via evaporation/condensation, (4) reflecting sunlight when frozen, and (5) absorbing CO2.