Climate 2.2

What are anthropogenic causes?

Anthropogenic causes are caused by mainly human activities.

They comprise of burning of fossil fuels and changing of land use.

Greenhouse effect

When greenhouse gases in the earth’s atmosphere traps long wave radiation emitted from the earth’s surface

Shortwave radiation VS Longwave radiation

Shortwave radiation is emitted from the sun to any surface (clouds, greenhouse gases, earth’s surface)

Longwave radiation is emitted from the earth’s surface to any surface ^

Enhanced greenhouse effect

Enhanced greenhouse effect is caused by the increase of anthropogenic causes that increased the amount of GHG in our atmosphere, which leads to more heat getting trapped in our atmosphere and global temperatures rising.

Enhanced greenhouse effect is just the presence of more greenhouse gases that cause more heat to be re-emitted onto the earth

How anthropogenic causes/factors lead to the enhanced greenhouse effect

Burning of fossil fuels releases greenhouse gases

Changing of land use to create energy releases greenhouse gases

How burning of fossil fuels increase the amount of greenhouse gases/ lead to the enhanced greenhouse effect

Fossil fuels have high carbon content → releases large amounts of carbon dioxide and other greenhouse gases when burnt

Burnt to create energy for human activities

For example, since 1880s (start of Industrial Revolution), burning of fossil fuels contributed to more than 35million tonnes of carbon dioxide emissions per year.

What are the 3+1 reasons as to why there is a change in land use?

Agriculture, Industries, Urbanisation, Deforestation

Deforestation for what

Deforestation to make:

Space for agriculture, industrial, urbanising spaces

Resources for human demand and infrastructure (timber and wood to make paper and building materials)

How deforestation leads to enhanced GHG

When large scale deforestation occurs,

There are less number of trees to take in carbon dioxide and lower levels of carbon dioxide in the atmosphere during photosynthesis

Trees release stored carbon dioxide during photosynthesis when chopped down, releasing the carbon dioxide back into the atmosphere

The soil is now exposed to the air, the carbon in the soil reacts with the oxygen in air to produce even more carbon dioxide that increases GHG in the atmosphere (Carbon oxidation)

For example, globally, deforestation contributes to around 20% of annual GHG emissions

How agriculture leads to enhanced GHG

As global populations increase, the demand for food increases

More forests are being cleared for the space to build farms harvesting fields for crops

Burning of fossil fuels to produce energy for farm machinery

Nitrogen in chemical fertilisers form nitrous oxide in air which contributes to enchanted greenhouse gas emissions (Nitrogen oxidation)

Animal waste gives out greenhouse gases

Globally, agriculture contributes to around 30% annual greenhouse gases

For example, cow waste gives out methane, which is a greenhouse gas

How industries lead to enhanced GHG

Burning of fossil fuels to create energy for machinery in industrial production

Changing of land use and deforestation to make way to build industrial infrastructure to meet human demands

Globally, industries contribute to around 43% of annual greenhouse gas emissions

How urbanisation leads to enhanced GHG

Burning of fossil fuels to power urbanised areas such as vehicles, as well as household activities such as heating, cooling and lighting

Changing of land use, clearing of forests to make space for the development of urbanisation

Globally, urbanisation contributes to 78% of the world’s energy and contributes significantly to the emission of greenhouse gases