What is Climate Change?

A hand holds a small globe

Scientists have known since the early 1800s that greenhouse gases such as CO2, methane and nitrous oxide in the atmosphere trap heat. Since the Industrial Revolution (1750 onwards), human activity- through burning of fossil fuels, industrial processes, animal agriculture, and deforestation- has led to a rapid rise in these gases. Global CO2 emissions from human activity have increased by over 400% since 1950.

Since the pre-industrial period, human activities are estimated to have increased Earth’s global average temperature by about one degree Celsius and unless we change path, are on track for further warming up to three degrees by the end of the century. While this might not sound much, even two degrees of warming would have a catastrophic impact.

A two-degree warming scenario would include an estimated rise in sea levels of one meter due to melting sea ice, leaving up to 10 million people living in coastal areas vulnerable to flooding and displacement.

Species we rely on for pollination and crops, and all the world’s coral reefs, are likely to be driven to extinction under two degrees of warming. Flooding and extreme weather events are likely to increase, and draught and water shortages would leave us vulnerable to humanitarian disasters.


The Intergovernmental Panel on Climate Change (IPCC) is a scientific body formed of 195 member countries, tasked with making regular assessments of the most up-to-date scientific evidence on climate change to inform and advise governments. In 2018 the IPCC released its most urgent assessment to date. The report made clear that to avoid the worst effects of climate change, we need to limit global temperature rise to 1.5 degrees Celsius above pre-industrial levels. To achieve this global emissions need to be reduced by 40% by 2030 and to net-zero by 2050.

Responding to the report, many national and local governments have declared a Climate Emergency. This follows the historic Paris Agreement in 2015, where for the first time 196 countries formed a global treaty that seeks to limit warming to 1.5 degrees.

Watch this short video below for a 60 second overview.

26 May 2021
Last Updated
26 May 2021