BaCCC/Module 2/Lesson 1/Part 2
Global impacts and consequences of climate change
According to Secretary-General Petteri Taalas (WMO, 2021),
[t]he number of weather, climate and water extremes are increasing and will become more frequent and severe in many parts of the world as a result of climate change. That means more heatwaves, drought and forest fires. More water vapor in the atmosphere has exacerbated extreme rainfall and flooding, and the warming oceans have affected the frequency and extent of the most intense tropical storms.
Climate change has also increased extreme sea level events associated with some tropical cyclones, which have increased the intensity of other extreme events such as flooding and associated impacts. This has augmented the vulnerability of low-lying megacities, deltas, coasts and islands in many parts of the world.
When carbon dioxide and other greenhouse gases trap heat in the atmosphere, that extra heat energises the atmosphere, disrupting and destabilising the global climate. (It is somewhat more complex than this, as you learnt in Module 1.) Let us have a look at the impacts we are experiencing across the globe.
| Climate change impacts and consequences around the world |
|---|
| Extreme weather events: Climate change is leading to more frequent and/or more severe (and sometimes longer lasting) extreme weather events, such as heatwaves, cold snaps, floods, droughts and wildfires. |
| Changes in precipitation patterns: Climate change is causing changes in rainfall patterns, leading to increased drought in some areas and more intense rainfall and flooding in others – and sometimes flooding following drought (parched land cannot absorb water) or deforestation, which can lead to landslides. (It is important to note that the impacts and consequences of flooding can be worsened by human activities such as building homes on flood plains, covering more and more land with concrete and asphalt, planting shallow-rooted non-native plants that get swept away, allowing debris to collect around bridges, etc.) |
| Rising sea levels: As global temperatures rise, the polar ice caps are melting and warming oceans are expanding, leading to rising sea levels that threaten coastal communities around the world, especially during high tides and storm surges. |
| Consequences for agriculture and food security: Changes in temperature and rainfall patterns can have significant impacts on crop yields and food production, leading to food insecurity and malnutrition in some regions. In some places, the rise in the sea level is salinating soils, making it difficult, if not impossible, to grow food crops. |
| Health consequences: Climate change is exacerbating existing health problems and creating new ones, including increased risk of heat stroke, respiratory illness and the spread of disease-carrying mosquitoes and ticks. The same goes for drinking water supplies, which are drying up or being contaminated by floodwaters. Furthermore, climate change events have repercussions for people’s mental and emotional health. |
| Biodiversity loss: Climate change is causing the loss of habitat and biodiversity, leading to the extinction of many plant and animal species and contributing to the sixth mass extinction, which is being driven by human activity (especially habitat destruction). |
| Economic consequences: Climate change is having significant economic impacts, including damage to infrastructure, property and crops, as well as increased costs associated with adaptation and mitigation efforts. (However, it should be noted that the costs of not mitigating and adapting are much higher.) |
| Social breakdown: Research shows that heatwaves increase aggression and violence. Women in some parts of the world are describing an increase in sexual harassment and assault. As clean water sources dry up due to drought, women are having to spend more time and travel longer distances, sometimes in the dark, to fetch water for their families. This leaves them more vulnerable to non-human – and human – predators. |
| These are just a few examples of the impacts of climate change around the world. The specific impacts can vary depending on the region, the severity of climate change and the resilience in that area. |
Table
| Algae blooms | Earthquakes or volcanoes | Melting ice caps | Reanimated viruses | ||||
|---|---|---|---|---|---|---|---|
| Loss of pollinators | Extreme cold | Melting Arctic sea ice | Sea level rise | ||||
| Climate refugees | Financial hardship | Melting glaciers | Shutdown of Atlantic Meridional Overturning Circulation (AMOC) | ||||
| Coral bleaching | Floods | Methane releases | Species extinctions | ||||
| Crop failures | Food or water shortages | Ocean acidification | Storms | ||||
| Desertification | Forest dieback | Ocean deoxygenation | Supply chain collapse | ||||
| Diseases | Heatwaves | Ocean heating | Unemployment or poverty | ||||
| Droughts | Hunger or famine | Permafrost thaw | War or conflict | ||||
| Dried-up water spots | Infrastructure collapse | Price instability | Wildfires |
Can you think of any others?
Climate change impacts will have grave consequences for sustainable development, including breakdowns in social cohesion, human health and well-being, peace, ecosystems and economic development. Every single Sustainable Development Goal will be negatively impacted by climate change. Watch the video The Impacts of Climate Change (1:50) to get thinking about climate change impacts on the economy:
You can adjust the playback speed and/or turn on subtitles/captions.
If you have trouble accessing the video, a summary is available below.
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Climate change is causing a wide range of impacts on natural and human systems, many of which have been expected based on scientific models and observations. However, there are also some surprising and unexpected impacts that have been observed or predicted, including the following:
| Surprising and unexpected impacts of climate change |
|---|
| More severe allergies: Warmer temperatures and higher levels of carbon dioxide can stimulate the growth of allergenic plants, leading to more severe allergic reactions in susceptible individuals |
| Increased risk of infectious diseases: Rising temperatures and changes in precipitation patterns can create conditions that favour the spread of diseases such as dengue fever, Lyme disease and malaria, including to and in the so-called developed world. |
| Changes in migration patterns: Changes in temperature and precipitation patterns can alter the timing and routes of animal migration, potentially disrupting ecosystems and affecting agriculture, fisheries and the ranges of plant species. For example, if predators arrive at the normal time, but their prey is not there yet, they may starve. |
| More lightning strikes: Warmer temperatures can increase the likelihood of lightning strikes, which can pose a risk of wildfires and other hazards. In places that are not used to lightning storms, people are being struck by lightning and killed. |
| Changes in ocean currents: Melting ice and changes in wind patterns can alter ocean currents, potentially disrupting global weather patterns and affecting marine ecosystems. Indeed, if major ocean currents slow down or stop their distribution of heat and nutrients around the world’s oceans, this has the potential of turning the oceans into giant sewers. |
| A triple threat to the oceans: First, sea surface temperatures are at record highs, which slow down the vertical mixing of nutrients in the oceans. Next, oceans absorb carbon dioxide, which becomes carbonic acid, leading to ocean acidification. Finally, because oxygen is less soluble in warmer water, ocean heating leads to the deoxygenation of the oceans. |
| Everything is happening earlier than expected: Scientists and climate change models have tended to err on the side of conservative estimates, not precaution. That is one reason we are seeing all sorts of climate change impacts happening much sooner than predicted.
Emissions are growing much faster than we’d thought, the absorptive capacity of the planet is less than we’d thought, the risks of greenhouse gases are potentially bigger than more cautious estimates, and the speed of climate change seems to be faster. — Sir Nicholas Stern, United Kingdom economist |
These unexpected impacts of climate change underscore the complex and interconnected nature of the climate system and highlight the need for continued research and action to address this urgent global challenge.
