Module 1: Introduction to climate change Copy

No. “Global warming” refers to an increase in the average temperature near the Earth’s surface. “Climate change” refers to the broader set of changes that go along with global warming, including changes in weather patterns, the oceans, ice and snow, and ecosystems. Most experts now use the term “climate change” because it gives a more complete picture of the changes that are happening around the world.

The main reason the climate is changing is because people are adding greenhouse gases to the atmosphere. The most important greenhouse gas is carbon dioxide, which is released whenever people burn fossil fuels to do everyday activities like driving cars, heating buildings, and making electricity. As greenhouse gases build up in the atmosphere, they cause the Earth to trap extra heat, making the planet warmer.

Climate change is never the sole cause of an extreme-weather event, but it can sometimes be a significant contributing factor. The ability of science to tell how much more likely a particular event may have been due to climate change has rapidly advanced in the past decade. For instance, the extreme rainfall that led to devastating floods in northern Europe in July 2021 were 1.2 to 9 times more likely to happen due to climate change (see summary and link to report here), and the record-breaking heatwave in parts of Canada and the US in 2021 would have been virtually impossible without the influence of human-caused climate change. Scientists have higher confidence in attributing events such as extreme cold, heat, and rain/snowfall to climate change, while events such as thunderstorms, cyclones and wildfires are more difficult to attribute.

Climate is far from the only factor: population is increasing in cities, more and more people are concentrated on vulnerable coastlines, and we have built homes and other infrastructure that is exposed to the path of storms. These vulnerability and exposure factors are in part driving the increasing damages we observe from disasters. At the same time climate change is leading to an increase in the frequency and/or intensity of hazards such as heatwaves, floods, droughts, and storms, amplifying the risks faced by vulnerable and exposed people. So the increasing disaster impacts are caused by the combined effects of  vulnerability, exposure and changing climate risks. It is highly likely that these trends will continue.

Yes! The 2021 ‘Assessment Report’ from the Intergovernmental Panel on Climate Change (IPCC), where more than 200 scientists from 66 countries have worked together to assess all available knowledge on climate change conclude that “It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred.” See here Seven key humanitarian insights from the latest IPCC report.

The world has already warmed about 1°C above pre-industrial levels, and 2°C or 1.5°C, have long been used as long-term temperature ‘goalposts’ for climate change mitigation. A warming of 1.5°C is not safe for most countries; it presents serious risks to human and natural systems, with a high probability of irreversible changes – and at 2°C it will get even worse (see IFRC summary and link here and short graphics on this WWF site). For instance, in the tropics, loss of maize crop yields will likely double between 1.5°C and 2C°C and heatwaves increase from 2 to 3 months. We need to act now to avoid serious consequences.

1. As summarized in the 2021 ‘World Disaster Report’:

• During the past ten years, 83% of all disasters triggered by natural hazards were caused by extreme weather- and climate-related events, such as floods, storms and heatwaves.
• The number of climate- and weather-related disasters has been increasing since the 1960s, and has risen almost 35% since the 1990s.
• The proportion of all disasters attributable to climate and extreme weather events has also increased significantly during this time, from 76% of all disasters during the 2000s to 83% in the 2010s.
• These extreme weather- and climate-related disasters have killed more than 410,000 people in the past ten years, the vast majority in low and lower middle-income countries. Heatwaves, then storms, have been the biggest killers.
• A further 1.7 billion people around the world have been affected by climate and weather-related disasters during the past decade.

Finally, the IFRC 2019 report ‘The cost of doing nothing’ estimates that the number of people in need of humanitarian assistance could double (from 108 to around 200 million people) between 2018 to 2050 due to climate-related disasters and the socioeconomic impact of climate change.

People cannot directly prevent extreme weather events such as heatwaves, heavy rainfall and drought. However, we – as individuals and as Red Cross Red Crescent Movement actors – can help limit the impact by preparing for more extreme events, and we can all contribute to stop further warming and thereby prevent global warming from exceeding the 1.5°C or 2°C thresholds.