Climate Change Flashcards
What is climate change?
Climate change is a large-scale, long-term shift in the planet’s weather patterns or average temperatures. Earth has had tropical climates and ice ages many times in its 4.5 billion years.
Quaternary geological period
The quaternary period is the last 2.6 million years. During this period temperatures have always fluctuated. Today’s temperature is higher than the rest of the period. Despite alternate cold and warm moments within this period, global temperatures have increased above average in the past 100 years. This current trend is what’s become know as global warming.
Natural Greenhouse Effect
The Earth is kept warm by a natural process called the Greenhouse Effect. As solar radiation hits the Earth, some is reflected back into space. However, greenhouse gases help trap the sun’s radiation. Without this process, the Earth would be too cold to support life as temperature would average as -18°C instead of +15°C.
Enhanced Greenhouse Effect
Recently, there has been an increase in humans burning fossil fuels for energy. These fuels (gas, coal and oil) emit extra greenhouse gases. This is making the Earth’s atmosphere thicker, therefore trapping more solar radiation but causing less to be reflected. As a result, our Earth is becoming warmer.
Linking CO2 and Global temperatures
The rate of carbon dioxide and increase in global temperatures is strong. Scientist agree that this increase is cause by human activity.
Evidence for climate change
Geological fossil evidence
Plants and animals fossils/remains which favour certain environmental conditions have been found in contractionary conditions, thus suggesting periods of a warmer and colder time. E.g. Mastodon in USA.
Evidence for climate change
Ocean sediment
Layers of sediment that has built up over time have provided scientist trapped oxygen isotopes. Scientist have used them to calculate and understand that atmospheric temperature have indeed changed.
Evidence for climate change
Ice cores
Ice cores are made up from different layers that each represents a different historical time. By exploring the water molecules of these cores, scientist have calculated fluctuating temperatures of the atmosphere.
Evidence for climate change
Historical records
Historical records from ancient cave paintings, diaries and written observations have provide evidence of climate change through personal accounts from the people through them.
What is the Little Ice Age? (1300-1870)
The Little Ice Age was a period of cooling that occurred after the Medieval Warm Period in parts of Europe and North America.
What were the impacts of the Little Ice Age?
- Price of grain increased and vineyards become unproductive.
- Sea ice engulfed Iceland and the sea force around parts f the UK. Frost Fairs were held on rivers such as the River Thames.
- People suffered from the intense cold winters as food stock were limited.
Greenhouse Gases
Carbon dioxide
Accounts for 60% of the enhanced greenhouse gases. It is produced by burning fossil fuels through producing electricity, industry, cars and deforestation.
Greenhouse Gases
Methane
Accounts for 15% of the enhanced greenhouse gases. 25x more efficient than Carbon dioxide. Produce from landfills, rice and farm animals.
Greenhouse Gases
Halocarbons
Human made and makes a tidy proportion of all greenhouse gases. 15000x more efficient at trapping radiation than Carbon dioxide. Produced from air-conditioning, refrigerators and aerosols.
Greenhouse Gases
Nitrous oxide
Accounts for 6% of the enhanced greenhouse effect. 250x more efficient than Carbon dioxide. Produced from fertilisers and car exhausts.
Recent Evidence for climate change
Global temperature data
Evidence collected by NASA suggests average global temperatures have increased by more than 0.6°C since 1950.
