Climate change Flashcards
How many major ice sheets have there been in the last 1 mil years
10
When and where was the last major ice sheets
20,000 years ago in Scottish Highlands
What is it called when there is 20% colder winters every 100,000 years
Albedo affect
What is the Quaternary period
Last 2.6 million years
What happens during warm spells
Ice retreats and opens glacial landscapes
Megafauna go extinct (e.g. woolly mammoths
How long do glacial’s last
100,000 years
How long do interglcials last
10,000 years
Evidence of recent climate change
Global temperature data from over 1000 weather stations across the world - highly accurate
Sea level rise measured using tide stations and satellite laser altimeters - highly accurate
Shrinking ice sheets and glaciers measured using a grid of ablation stakes (poles of wood or plastic) and seeing if they move over time, front of glacier must be checked constantly
Evidence of historical climate change
Tree rings - dating trees to the exact date they were formed, can give climatic conditions for each year - narrow rings during cold climate - wider rings during warmer climate, problems are only shows local climate - different species grow at different rates, forest fires and animal influence
Ice cores - analyse the trapped water molecules - can give accurate dates and temperature of atmosphere, helps create many accurate historical climate graphs, past 400,000 years - accurate
Historical paintings and dairies - not accurate
3 natural climate change theories
Sunspot theory - sometimes the sun has little black spots on it, less spots mean less solar energy - more spots mean more solar energy reaching earth
Eruption theory - big volcanic eruptions produce lots of smoke + ash, spread around the earth, block suns radiation lowering temp
Orbital theory - orbit can change in 3 ways, sometimes axis tilts or wobbles, or orbit is more circular, these alter the amount of radiation earth receives
Describe enhanced greenhouse effect
suns energy arrives as short wave - reflected off of earth as long wave - human activity leads to increase of greenhouse gasses - less radiation can escape into space, trapped heat warms earth
Causes of greenhouse gasses
Vehicle exhausts, burning fossil fuels, electricity in homes, deforestation, industrial processes
Which greenhouse gas has the most warming power
Flourinated gasses, 3000x more powerful than CO2
What is the greenhouse effect?
Layer that traps suns radiation to heat the earth
Social effects of climate change in the UK
Elderly become vulnerable during heat waves, but less cold related deaths
Increased flood risk on lowlands, may become sever affecting housing and infrastructure