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The human causes of climate change are largely responsible for increasing the Earth’s temperatures. These causes of global warming have been in the media a lot in recent years. Human factors are the result of growing world population and economic developments.

They include:

• The burning of fossil fuels for transport, industry and power, producing carbon dioxide and increasing global warming
• Increased car exhaust emissions have resulted in more nitrous oxide in the atmosphere. Nitrous oxide is 200-300 times more effective in trapping heat than carbon dioxide
• The increased production and use of fertilisers to meet worldwide food demands also adds to the amount of nitrous oxide in the atmosphere
• Worldwide deforestation, often involving rainforest burning, produces carbon dioxide. In 2021, the Amazon rainforest was reported in the media to emit more CO2 than it absorbs. In other words, it is now a carbon source and no longer a carbon sink
• CFCs found in fridges and aerosols, and as a by-product of the production of polystyrene packaging destroy ozone in the upper atmosphere. The coolants used in air conditioning systems create CFCs, and must be disposed of properly
• Methane gas is released from landfill sites as waste decomposes; because methane is a stronger greenhouse gas, small increases have a larger impact on climate change
• Peat bog reclamation e.g. in Scotland for the building of wind farms has resulted in additional carbon dioxide released into the atmosphere
• The increase in paddy fields to feed rapidly growing populations in Asian countries has increased the amount of methane
• The demand for beef has increased methane levels produced from both ends of cattle and animal dung

The main greenhouse gases in the atmosphere are carbon dioxide, methane, and nitrous oxide. They are naturally occurring in the atmosphere but have increased through the burning of more oil, petrol and coal, at the same time as forests have been removed.

The build-up of greenhouse gases in the atmosphere is the result of more heat being retained than would usually be the case. Naturally, the radiation from the sun would be reflected back into space. However, the increased greenhouse gases trap some outgoing infrared radiation keeping the Earth warmer than it might otherwise be.