The greenhouse effect and global warming

In a nutshell

The greenhouse effect keeps the Earth warm. However, the enhanced greenhouse effect has led to climate change. Countries around the world are working together to reduce greenhouse emissions.

Greenhouse effect

Greenhouse gases contain bonds which absorb infrared radiation and bounce it back out in all directions, including towards the Earth. The re-emission of radiation is what keeps the Earth's atmosphere warm. This is known as the greenhouse effect.

Bonds which absorb IR radiation	greenhouse gas
$C=O$	Carbon dioxide
$O-H$	Water vapour
$C-H$	Methane

Enhanced greenhouse effect

The increasing population and industrialisation combined with deforestation has led to a great increase in carbon dioxide and methane in the atmosphere. This has led to more heat energy getting trapped in the Earth's atmosphere, making Earth warmer - this is known as global warming.

It is agreed that global warming is the reason for the changes in climate, such as polar ice caps melting, floods, drought and the extreme heatwaves and wildfire in countries which have never reached such record high temperatures, ranging from $40 \degree C$ in the UK to $60 \degree C$ in the Middle East.

Chemistry; Alcohols and haloalkanes; KS5 Year 12; The greenhouse effect and global warming — A: Temperature difference / $\degree C$ ; B: Atmospheric concentration of $CO_2 \, (ppm)$ ; C: Past (thousands of years); D: Present time.

There is scientific evidence showing an alarming increase in temperature correlating with the amount of carbon dioxide being released into the atmosphere. You cannot always state that one factor causes a particular outcome as correlation does not always prove a link between the two. However, through research, scientists have come to an agreement that global warming is happening due to human activity.

Global warming

Governments have been persuaded by scientific evidence to put systems in place and globally work together to reduce greenhouse gas emissions. The Kyoto Protocol (ended in $2012$ ) was signed by industrialised countries, including the UK, to reduce the emissions of greenhouse gases. Recognising the impact it has on the environment, the UK government has introduced policies to use more renewable energy sources, where possible.