Human Influence on climate and the greenhouse effect and Climate Change Flashcards
Climate Change
The Earth’s climate has been fluctuating naturally throughout history.
There has been seven cycles of glacial retreat and advance in the last 650,000 years as temperatures on Earth change.
The current warming trend has a greater than 95% probability of being the result of human activity.
A major contributor to climate change is the greenhouse effect.
Natural Greenhouse Effect
The greenhouse effect is a natural process that warms the Earth.
Solar energy passes through the atmosphere and is absorbed by Earth’s surface, heating the planet.
Some of this energy is then radiated back up in the form of heat.
Some heat escapes back into space, but most gets absorbed by atmospheric gases and redirected back to 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.
This means that the Earth is slowly heating up.
Most CO2 release methods
Humans have released excess CO2 into the atmosphere, mostly through:
Burning fossil fuels for energy
Deforestation and burning of forests (a carbon sink)
Evidence for climate changes - Global Temperature Changes
An increase in greenhouse gases has resulted in more heat being trapped in the atmosphere.
This has resulted in both surface and ocean temperatures throughout the world increasing.
Evidence of climate change - Rising Sea Levels
The increase in global temperatures means more melting of the 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.
The graph shows an increase in global mean sea level using a combination of tidal readings and satellite data.
Evidence for Climate Change - Loss of Cover
The increase in global temperature translates 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.
Impact of Climate Change on Australia
Climate change is putting pressure on our planet.
The gases released through burning fossil fuels trap more heat in the atmosphere, causing more extreme and unpredictable weather.
We are experiencing more frequent heatwaves, longer droughts, longer and more severe fire seasons and more intense storms.The number of days that break heat records has doubled in the past 50 years.
Higher temperatures are causing longer droughts in some areas of Australia.
In other areas, increased evaporation is causing heavier rainstorms and flooding. As the oceans warm, more coral reefs are bleaching.
This means many fish and other marine life lose their habitats.
Many animals and plants in both marine and terrestrial habitats have to shift where they live to stay within habitable environments.
To keep up with temperature changes, some plants and animals are maturing and reproducing at different times.
This means the food sources that each one relies on, such as seeds or berries, may not be available when needed.
