Introduction to climate change (in depth)

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Introduction to climate change

Make sure to do the Quiz at the end of the page! Jump directly to it by clicking here.

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. Now, we know that greenhouse gas concentrations are directly linked to climate change.

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).

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.

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.

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: Getting a grip on GWP – i.e. ‘global warming potential’

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’!

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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: The ‘hockey stick’ of CO2 emissions

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?

A growing body of evidence shows that a warmer Planet is a potential threat to all living things. Here are three related concepts to be aware of:

• Tipping points refers to changes that lead to irreversible damage in a given ecosystem. When permafrost thaws in Arctic areas, for example, the ground releases huge volumes of CO2 and methane (another GHG) that had been safely stored for centuries. In fact, scientists estimate that permafrost areas hold roughly twice as much CO2 as currently circulates in the atmosphere. Its release, whether fast or slow, would be catastrophic. Other tipping points include the collapse of ice sheets in Arctic and Antarctic areas and die-off of tropical coral reefs.

• Domino effect refers to when crossing the tipping point in one area triggers a cascade of other events. In one scenario modelled by the IPCC, as ice sheets melted, the additional cold, glacier meltwater caused a major current in the Atlantic Ocean to slow down. Ultimately, this significantly reduced rainfall in the Amazon rainforest. In the worst-case scenario, the lush, dense rainforest became a savanna with smaller trees widely dispersed over a much drier grassland.

• Threat multiplier effect captures how climate change effects can interact with – and exacerbate – pre-existing threats. Severe drought, for example, can prompt farmers to abandon their lands and move to urban areas, disrupting food supplies. As water resources become scarce, it can trigger civil unrest. If a large region is affected, it may even result in conflict or war among nations.

How is climate change already affecting people?

Already, heat waves, severe storms and floods, and massive forest fires have forced millions of people around the World to relocate – sometimes on very short notice! In some cases, the move is temporary; in others, entire villages or towns have been destroyed. When this happens, people are said to be climate change refugees.

Watch this: Climate refugees: Nations under threat

Even today, people who have lived on remote islands are being forced to relocate as the sea level begins to rise, even by a few centimeters. Several coastal mega-cities are looking for ways to deal with the same threat (see climate change mitigation adaptation and resilience also climate justice].

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But extreme events are not the only problem. Gradual warming of the Planet is expected to have negative impacts on human health and influence how people earn a living or carry out daily activities. It also threatens to disrupt essential services that underpin societies, such as access to clean water and affordable electricity.

Sooner or later, climate change will affect everyone, whether directly or indirectly. But there is also reason for hope. Explore more Yconic content to see what people are doing to save the Planet.

Investigate further: Is climate change already affecting your local area?

Almost everyone is feeling some effects of climate change, whether through heat waves, torrential rain or nearby forest fires. Can you find evidence that climate change is already damaging local ecosystems? Is anybody doing something to address these environmental impacts (e.g. the government, non-governmental organisations, local people)? What might people have to do to cope with hotter summers or colder winters? Or more or less rainfall?

Act now: Collect an ‘oral history’ about weather, climate or climate change

Grab your smart phone and find an older adult – e.g. your parents or grandparents, a teacher or coach, or an elderly neighbour. Plan a few questions about how the weather or climate in your city or region has changed over their lifetime? Ask also about how the energy they use has evolved. Hit ‘record’ on an audio app and get them to tell their story! Make sure you get their permission to upload the recording to Yconic!

Act now: How do YOU experience weather…and climate change?

Have you read articles about how global warming is affecting your local environment? What do you know about what might be causing higher emissions locally? Have any news stories about extreme weather events been linked to climate change? What was your personal experience of these events? Hop over to the Yconic Forum to share your thoughts and experiences with other Yconickers.

Quiz time

Test your knowledge and express your ideas on climate change.

Yconic is keen to know what you learned about climate change – and what you think about it! Click through to create your very own page. This page will be linked to your personal profile. But please remember: because this is a wiki platform, others may be able to find and read it. While they cannot ‘edit’ your page, they might comment on it – which is a GREAT way to encourage more discussion:

Go to Climate Change Quiz

See your results

Each user has a personal results page for each of the questionnaires (basics and in-depth). Use the links below:

• First, create your results page. Simply click this link, and save the page.
• Once you save the page you can see your results:
  • View my results: Open my results page

References