Introduction to Environmental Change Flashcards
Why study past environmental change?
It allows us to understand past climate and therefore make accurate future climate predictions.
This benefits society; it is easier to convince people to act against global warming, it helps us predict flood and droughts etc.
How are climate models tested?
They are ran backwards and tested against paleoclimate reconstructions. If they match then they’re then used to predict the future.
What are proxies? Give examples
Physical, chemical or biological records that respond to changes in temperature or precipitation, e.g. stable isotopes, pollen etc. They are found in archives.
What are archives? Give examples
Archives are something containing proxies e.g. lake/ocean sediments, glaciers, trees, ice cores, peat etc.
What is the difference between a proxy and an archive?
A proxy is what we USE to identify climate. An archive is what contains the proxies.
What is thermal expansion?
When the size of water/the sea expands because it gets hotter.
What is an Ice Age?
An Ice Age is when there is extensive glaciation in the northern and southern hemispheres.
What periods of time to ice ages contain?
Warmer periods (interglacials) and cooler periods (glacials).
What Ice Age are we in now? How long has it lasted?
We are in the Quaternary Ice Age which has lasted for the past 2.6 million years.
What year is the oldest weather record we have and where was it taken from?
1659, recorded in the UK.
Why are closed lakes useful for palaeolimnology?
Their water level only goes up and down depending on the climate. These changes can be reconstructed by drilling into lakes, collecting sediment cores and analysing their proxies.
What are isotopes?
Different types of an element.
Why can isotopes work as proxies from closed lake sediment archives?
Because chemical composition of the lake depends on climate (how much precipitation there is). Isotopes can therefore tell us when there were drier and wetter periods.
What is radioactive carbon dating used for?
It is used to date organic matter for example bones.
