Week 6

25% in ocean 25% in land/biosphere 50% in the atmosphere

they have pertrubed the balance between the resevoirs- they are imbalanced and their sizes have been altered human influences are not balanced from the changes in fluxes

The earth recieves more energy in the tropics than at high latitudes the difference in heating fuels the circulation of the atmosphere, which works to transport excess heat from the tropics to the poles the ocean also transports energy from the tropics to the poles - but less efficiently than the atmosphere

Greenland and Antarctica 1km or more per year of flow - fast for a glacier

there is rapid cycling due to plants photosynthesising and respiring and decomposing this can remove Co2 but also put it back in - cant remove all the Co2 from the atmosphere but the fluxes can be large

they are roughly balanced - changes in reservoirs are not huge without the impact of humans

• extracted carbon from the geological reservoir through ff • through land use change such as deforestation • cemend production nb this perturbation cannot be balanced easily because it takes a long time to put carbon back into the geological reservoir about 3 petagrams of carbon a year but sufficient to perturb the system

there are very small fluxes in terms of the formation of new rocks - however this takes time there are volcanoes fossil carbon is being redistributed into different places in the atmosphere - and there is more in the ocean as well

plants takeup Co2 and emit oxygen in photosynthesis since plants need Co2 to grow this can increase in higher Co2 climate however there is a limit and doesn’t apply to all plants using satellites it is clear that there has been an increase in the size of the land res. because of an increase in Co2

the idea that organisms take up Co2 as they grow deposit this back onto the sea floor wen they die and sink this forms ff in eons

CO2 is direclty taken up by seawater • you can dissolve Co2 in the water - Co2 can be dissolved in the water under high pressure- once you release the pressure CO2 can escape

Carbonic acid lowers the ph - higher acidity

Day to day or month to month variation

4km

sea level would rise by 40m

We used to have massive ice sheets over the land which pushed the land underneath down - these have now gone but the land is still responding to this and is moving upwards therefore we need to account for the changing in the height of land surface to ensure a good understanding of sea level rise

in the future with more emissions, there will be more warming and thus sea level rise there is more sea level rise regardless of the scenario due to the delay in ocean response - high heat capacity

There have been large changes over 500 m yrs last 10k yrs have been relatively stable but the temperatures are uncertain and may not be representative of the entire globe - use of proxies there have been glacial/interglacial cycles over periods of about 100,000 yrs

paleoproxies = indirect evidence of former cliamte conditions eg. tree rings, isotopes of oxygen and carbon, fossilised pollen and plankton, lake and ocean sediments, animal bones, charcoal and landscape feature req. when there are no direct measurements of climate variables - eg. temperature or precipitation eg. Dome C ice core in Antarctica - about 800ys of records for climate - very detailed paleoproxy

The cause for the glacial cycles lies in variations in the earths orbit the earths orbital parameters vary naturally over this of yrs with regular or predictable cycles

Eccentricity - how oval/circle shaped the earths orbit is (eggs centricity) the bigger the eccentricity the more oval it is - the bigger the variation, when it is less eccentric more circular and get less variation Obliquity - the angle of the tilt - varies how strong the seasons are Precession - spin around the earths axis - i.e. the idea that the location of the north star changes- sometimes it is close to polaris and sometimes close to valaga these all change on different time scales however, together the parameters control the spatial distribution of insolation, and the seasonal cycles

• variations in the northern hemisphere summer insolation is critical for glacial cycles • weaker summer insolation in NH favours coolder climate Growth of land ice controlled by the accumulation in the summer - mainly down to summer temperatures - if you glacier melts away completely in the summer then is it harder to have a glacial period • global ice volumes have varied in tandem with temp over global cycles • large ice sheets in NH - ice sheet changes are associated with large positive albedo feedback

warming leads to Co2 release from the oceans however the mechanism is not entirely certain the effect is that CO2 changes are a large positive feedback in the glacial and interglacial cycles could be the microphysical processes at the top of the ocean - turbulence effects the solubility at the top of the ocean - net flux of Co2 going out at certain points therefore temperature increases - impacts the solubility of te oceans

20,000 yrs ago