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The triple planetary crisis
Learn what the triple planetary crisis is, and how human actions are disturbing Earth's balance.
Life on Earth depends on a delicate balance of living and non-living things working together, and human actions are upsetting that balance. Even small changes in global temperature, oxygen levels or the ozone layer can put life at risk.
The three biggest environmental problems today are climate change, biodiversity loss and pollution. Together they are called the triple planetary crisis.
Burning fossil fuels such as coal and oil releases greenhouse gases such as carbon dioxide and methane. These trap even more heat in the atmosphere and cause global warming. Normally the Earth keeps a balance, because trees, plants and even tiny ocean plankton take in carbon dioxide as they grow. But fossil fuels release extra carbon that was locked underground for millions of years, far faster than plants can take it up, so the heat builds up.
Even a small rise in temperature can melt ice caps and raise sea levels, which could flood many coastal cities, cause extreme weather, and make many plants and animals disappear. These long-term changes in temperature, rainfall and weather patterns are what we call climate change.
When natural habitats are destroyed, plants and animals can disappear and ecosystems are upset. As chapter 12 showed, if the grasses go, animals that feed on them, such as deer or grasshoppers, struggle; and without those herbivores, the predators lose their food too. Every kind of living thing has a role, and losing even a few weakens nature's ability to support life.
Pollution makes it worse. Air pollution from factories, vehicles and burning fuels causes breathing problems, damages crops, and leads to smog and acid rain. Waste from factories, farms and plastic harms water life, and too much fertiliser pollutes the soil and spreads harmful substances through the food chain.
Countries have made global agreements:
| Agreement | What it did |
|---|---|
| Montreal Protocol (1987) | cut harmful chemicals such as CFCs (chlorofluorocarbons), so the ozone layer is slowly recovering |
| Earth Summit (1992) | started international work on climate change and biodiversity |
| Kyoto Protocol (2005) and Paris Agreement (2015) | committed countries to cut greenhouse gas emissions; Paris set the goal of keeping global warming below 1.5 °C |
As of 2025, the world is not on track to meet that goal.
All of Earth's systems (hydrosphere, biosphere, atmosphere and geosphere) are connected, so damage to one affects the others. Protecting the climate means cutting greenhouse gases: using renewable energy such as solar and wind, using energy better, and travelling in greener ways. Protecting biodiversity matters too, because varied ecosystems are stronger and more balanced, and local communities can do a lot by using natural resources sustainably.
Everyone can help:
- reuse, repair and recycle things like clothes and plastic, to cut pollution and waste;
- save energy and water: small actions add up;
- learn more, share ideas and encourage others.
Keeping life going on Earth needs action from all of us, from local communities to world leaders.
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