Dramatic change

The changes to our climate that are happening now are caused by a very steep rise in the concentration of various gases in the air. Concentrations of these gases, known as greenhouse gases (GHGs), have risen steeply since the industrial revolution c.1750. Human activity - how we live our lives and the consequences of industrial activity - is the cause. 

These gases are called greenhouse gases (GHGs), because they let sunlight pass through the atmosphere to reach the earth but then trap the outgoing energy from the heated surface, which is similar to what happens in a greenhouse.

These GHG increases were initially triggered by the change from an economy based on manual labour to one based on machine manufacture, and have continued to grow as all aspects of our lives have become mechanised. Our global economy is based on infinite growth, but resources are finite, and the current system is not sustainable. 

Major GHG trends

The graph above using data from the Global Carbon Project (2020) illustrates the evidence for the upward trend in GHG levels. Fossil CO₂ emissions have grown substantially over the past two centuries and emissions over 2002–2018 were estimated at above 30 GtCO₂ /yr. Emissions in the 2000s as compared to the 1990s were higher in all regions, the rate of increase was largest in Asia. The increase in non-Western countries is due to an industrialization process that historically has been energy-intensive; a pattern similar to what the current OECD countries experienced before 1970.

Overall, this shows a clear and dramatic increase since 1750, which lends urgency to the development and implementation of mitigation and adaptation measures on a global scale. 

The Keeling Curve gives today's atmospheric CO₂ concentration and users can view weekly, monthly, decadal and millenial trends.