Introduction to climate change (in depth)
Introduction to climate change
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Climate change may seem like a recent phenomenon. But the idea that life on Earth is influenced by a ‘greenhouse gas effect’ first emerged in the early 1800s. While it wasn’t yet called that, scientists were already investigating causes and effects.
Springboard
- A brief history of climate change science
- Tipping points, dominoes and multipliers
- How is climate change already affecting people?
Weird weather? Or a changing climate
Almost 200 years ago, scientists found that certain gases in the atmosphere affected the Earth in two ways. First, by trapping heat from the Sun – rather than reflecting it back to the atmosphere – these gases kept the Earth’s surface temperature at around 14-15°C (57-49°F). For the record, without the greenhouse effect, the Earth's average surface temperature would plummet to −18 °C (−0.4 °F).[1][2]
In turn, this altered the energy balance – that is, the equilibrium between the energy the Planet gets from the Sun and the energy it ‘loses’ into outer space. Names to know in this early research include Joseph Fourier and Claude Pouillet.
In 1856, Eunice Newton Foote demonstrated that the Sun’s warming effect was stronger on air that contained water vapour than on dry air. Critically, she also showed that it was stronger where concentrations of carbon dioxide (CO2) were higher[3].
In turn, scientists began to look for clues about weather and climate patterns that pre-dated the data they could collect with the most advanced instruments of the day. The approach became known as paleoclimatology. They soon determined that past Ice Ages and other natural changes were likely linked to the greenhouse effect.
As the Industrial Revolution ramped up, some scientists argued that burning modern fuels (e.g. coal and oil) would push up emissions of the greenhouse gases (GHGs) previously identified. These include CO2, methane, chlorofluorocarbons, nitrous oxide and ozone.
Watch this
Lots of natural phenomena release GHGs. A key difference related to man-made emissions is that they often excel (in a bad way) at trapping heat in the Earth’s atmosphere. Keen to know how burning fossil fuels compares to letting cows pass gas? Or why CO2 is the ‘problem child’ of GHGs? How about the BIGGER, longer-term impacts beyond climate change? Just click ‘play’!
Tipping points, dominoes and multipliers
Fast forward – through a lot of studies across many different fields – to 1990. In its First Assessment Report, the United Nations’ Intergovernmental Panel on Climate Change (IPCC) built a solid case for the reality that GHG emissions linked to human activity are triggering climate change. And that the dominant trend was global warming.
What was the key evidence? A sharp rise in GHG emissions that corresponds with the use of fossil fuels for energy and for industry, the shift to large-scale agriculture and the destruction of huge areas of forest to make way for human activities.
Data dive
From 1750 to 1900, CO2 emissions remained remarkably stable, even as the global population started to grow. Compare that to the next 120 years – i.e. 1900 to today. Do these data support the scientific findings given above?
