Climate Change Background & History

Climate change refers to the long-term shifts in global temperature, precipitation, and other climate patterns. Over Earth's history, climate has changed many times, but the rapid warming we're experiencing today is unprecedented.

The Role of CO2 Emissions

Carbon dioxide (CO2) is a greenhouse gas that traps heat in the Earth's atmosphere. Human activities, primarily the burning of fossil fuels like coal, oil, and natural gas, have significantly increased atmospheric CO2 levels since the Industrial Revolution.

Climate Change Timeline

Climate change has been a topic of discussion for more than a century. Here's a timeline of the major moments in our understanding of Earth's climate.

  • Svante Arrhenius

    1896

    Swedish scientist Svante Arrhenius publishes the first study linking CO2 emissions to global warming.

  • Charles Keeling

    1958

    Charles Keeling begins measuring atmospheric CO2 levels at Mauna Loa Observatory in Hawaii, revealing a steady increase over time (the "Keeling Curve").

  • IPCC

    1988

    The Intergovernmental Panel on Climate Change (IPCC) is established to assess scientific, technical, and socio-economic information on climate change.

  • UNFCCC

    1992

    The United Nations Framework Convention on Climate Change (UNFCCC) is adopted, aiming to stabilize greenhouse gas concentrations in the atmosphere.

  • Kyoto Protocol

    1997

    The Kyoto Protocol, an international treaty to reduce greenhouse gas emissions, is adopted.

  • Paris Agreement

    2015

    The Paris Agreement is adopted, with the goal of limiting global temperature rise to well below 2°C above pre-industrial levels.

  • Greta Thunberg and Fridays for Future

    2018

    Swedish environmental activist Greta Thunberg begins a school strike for climate, inspiring the global youth-led movement known as Fridays for Future.

Climate Change Today

Today, the Earth is warming at a much faster rate than in the past. Scientists have concluded that the main cause of global warming is the greenhouse effect, a phenomenon that occurs when gases in the atmosphere trap the Sun's heat. The greenhouse effect is so named because of the way it works. Visible light from the Sun shines onto Earth, where it is absorbed and then radiates back into the atmosphere as heat. Some of the heat passes through the atmosphere, but most of it is absorbed by greenhouse gases and re-emitted in all directions, warming the surface of the Earth and the lower atmosphere.