Human Influence on climate Flashcards
Climate Change
A major contributor to climate change is the greenhouse effect.
There has been seven cycles of glacier retreat and advance in the last 650,000 years
as the temperature of the Earth changes.
The current warming trend has greater than 95% probability of being the result of human activity.
Natural greenhouse effect
Greenhouse effect is the process of warming up the Earth.
Solar energy passes through the atmosphere and is absorbed by the Earth’s surface, heating the planet.
Some energy is radiated by in the form of heat.
Some heat escapes into space. But some/most of the heat gets absorbed by atmospheric gases and is redirected back into Earth, causing further warming.
The gases that contribute to the greenhouse effect include carbon dioxide, water vapour, methane, nitrous oxide and ozone.
Enhanced Greenhouse effect
Since the industrial revolution in 18th and 19th centuries, the concentration of greenhouse gases has been increasing.
Human activities have increased concentrations of CO2 and other greenhouse gases in the atmosphere.
The increased concentration of these gases traps more heat causing the natural greenhouse effect to be amplified.
CO2 is released through
Burning fossil fuels for energy
Deforestation and burning of forests (a carbon sink)
This means that the Earth is slowly heating up.
Methane emissions have increased through, livestock, landfill and waste treatment have doubled since the last century.
Evidence for Climate Change
Global temperature changes
Rising Sea Levels
Loss of ice cover
Global Temperature changes
The increase in global temperature leadsz to more melting of glaciers and ice caps.
This results in less radiation being reflected from the surface, so more heat is absorbed by earth surface which leads to more ice melting - a positive feedback loop.
Earth’s ice contains thousands of years worth of carbon from the atmosphere stored away.
Melting of ice can cause this stored carbon, as well as other gases, to be released
Rising Sea Levels
Rise in temperatures leads to more melting of ice caps and glaciers.
This has resulted in an increase in sea levels as more water is released from the glaciers and added to the volume of the sea.
Loss of Ice covers
Earth’s ice contains thousands of years worth of carbon from the atmosphere stored away.
Melting of ice can cause this stored carbon, as well as other gases, to be released.
This results in less radiation being reflected from the surface, so more heat is absorbed by earth surface which leads to more ice melting - a positive feedback loop.
