mock only - Changing Climate

How are Milankovitch cycles linked to natural climate change

• Obliquity - changes in how much the Earth tilts on its axis

• Precession - the amount the Earth wobbles on its axis

• Eccentricity - changes in the shape of the Earth's orbit

What are sun spots

 

• Due to magnetic storms, there are dark spots on the sun's surface

 

How do sun spots lead to natural climate change

• The more sun spots there are, the more radiation the Earth receives

• This causes temperatures to rise

Are sun cycles permanent

• Sun cycles are on an 11 year cycle

• Though some cycles are longer than others e.g. The Little Ice Age

How do volcanic eruptions lead to natural climate change

• Super volcanoes are volcanoes that erupt more than 1000 km³ of material in a single eruption

• This means that huge amounts of dust (containing ash, sulphur dioxide, and water) are released into the atmosphere

• This dust blocks sunlight, resulting in cooler temperatures

Example of super volcano

• In 1991, Mount Pinatubo erupted

• It emitted 20 million tonnes of sulfur dioxide and ash into the atmosphere

• Over the next two years, Earth's average temperature fell by 1^o

What is the natural greenhouse effect

• Energy comes from the sun as shortwave radiation

• Most energy passes through a layer of greenhouse gases, warming the Earth's surface

• Some energy is reflected back out to space as a long wave radiation

• Long wave radiation does not pass through greenhouse gases as easily as shortwave radiation

• But some of it still escapes back out to space

• Some of it is absorbed by greenhouse gases and reflected back to Earth

What is the enhanced greenhouse effect

• Energy comes from the sun as shortwave radiation

• Most energy passes through a layer of naturally occurring greenhouse gases

  • Human activity has put more greenhouse gases into the atmosphere and made this layer thicker

• Some energy is reflected back out into space as long-wave radiation

• Long wave radiation does not pass through greenhouse gases as easily as short wave

• Some energy escapes back out to space

• The thicker layer of greenhouse gases absorbs more energy and more is reflected back to earth

• Earth gets warmer

What gases account for the enhanced greenhouse effect

• Carbon dioxide

• Methane

• Halocarbons

• Nitrous oxide

What activities release greenhouse gases

 

• Carbon dioxide - cars, industry, deforestation

• Methane - farm animals

• Halocarbons - air con, fridges

• Nitrous oxide - agricultural fertilisers

How has carbon dioxide emissions increased over time

• Since the industrial revolution, atmospheric carbon dioxide has increased by 150%

What does climate change cause

• Rising sea levels

• Extreme weather events e.g. Heatwaves

Social impacts of climate change (x4)

• Around the Maldives, sea water absorbs carbon dioxide, making it acidic

  • This reduces numbers of fish which local people rely on for food and income

• In 2022, over 2000 people died from heatwaves in the UK

• There is an increase of flooding due to climate change.

  • Lots of diseases spread through contaminated water

  • E.g. Cholera - 4000 deaths in 2023

• Pests can thrive in warmer temperatures e.g. Beetles

  • Some beetles attack coffee crops in Ethiopia; this impacts 700,000 families that rely on coffee for their income

Economic impacts of climate change (x3)

• With rising sea levels shutting down tourist resorts, the Maldives can no longer make its income from tourism

• During heatwaves, the farming industry can lose billions of pounds because crops and animals die

• With sea levels rising, water is becoming too salty to grow rice in

  • By 2050, the decrease in rice production may cost Vietnam 17 billion usd

Environmental impacts of climate change

• Lake Chad, which is used by 30 million people in Africa, has been shrinking due to less rainfall and lots of droughts