What is Climate Change?
When we talk about climate change, we’re referring to the build up of greenhouse gasses in the atmosphere due to human activity and which is driving a long term shift in the temperature and weather patterns of the earth, causing it to become hotter and more unstable.
The main greenhouse gasses are carbon dioxide, methane, and nitrous oxide, and these are released into the atmosphere by the burning of fossil fuels such as coal, oil, gas and petrol, and also by the use of modern fertilisers in agriculture and other agricultural practices such as intensive livestock farming. These gasses form a layer around the earth which acts like the glass surrounding a greenhouse, causing the earth to become hotter.
Although it is true that the climate of the earth has always slowly changed over time, since the industrial revolution of the 1800s human activity has been the overwhelming cause [1], and this has resulted in an unprecedentedly rapid rise in greenhouse gasses in the atmosphere. For example, the level of carbon dioxide alone rose by 40% during the 20th and 21st centuries, and is now higher than at any time in the last 2 million years [2].
Although the emissions of greenhouse gasses come from all over the world, some countries are responsible for more emissions than others. The United States and the European Union (including the UK), for example, are historically responsible for nearly 50% of all the carbon dioxide currently in the atmosphere, while China, Japan and India combined are responsible for about one fifth [5].
Although everybody and every country needs to take action, the people and countries that have produced the biggest share of greenhouse gasses have the greater responsibility to act first.
[1] https://www.ipcc.ch/report/ar6/wg1/downloads/outreach/IPCC_AR6_WGI_SummaryForAll.pdf
[2] https://www.metoffice.gov.uk/weather/climate-change/what-is-climate-change (possibly a better reference could be found, as this doesn't provide evidence for the 2 million year claim, it is just an authoritative source that makes the same claim)
[3] https://www.ipcc.ch/2021/08/09/ar6-wg1-20210809-pr/
[4] https://climate.mit.edu/ask-mit/why-do-some-people-call-climate-change-existential-threat
[5] https://ourworldindata.org/contributed-most-global-co2
As a result the average global temperature is also changing dangerously fast, and has increased by 1.1C since 1850, and this is set to continue increasing, with 1.5C expected to be reached within the next decade or two [3]. Without strong and sustained decreases in the emissions of greenhouse gasses this trend is set to increase even further to levels which pose an existential threat to life on earth and human civilisation as we know it [4]
