The Earth’s natural processes create and destroy greenhouse gases, but human activities are adding too many to the atmosphere. These emissions blanket the planet, trapping heat from the sun and causing global warming. As the climate warms, it changes weather patterns and alters the environment. This has already had a profound impact on people and other living things, with the effects most strongly felt by the world’s poorest countries and communities.

The most commonly cited cause of climate change is the burning of fossil fuels – coal, oil and gas — which releases large amounts of carbon dioxide into the air. These emissions are responsible for over 75 per cent of the Earth’s total carbon dioxide. But there are other factors that contribute to climate change, including deforestation, agriculture and land-use changes. In addition, sand and dust from deserts and volcanic eruptions can also affect the climate by blocking sunlight or absorbing it.

As the global temperature rises, the rate of melting of ice sheets and glaciers will increase. The ocean will also expand when it warms, raising sea levels. These effects will be especially severe in low-lying areas and densely populated coastal cities, such as New York City and Mumbai.

Natural disasters like hurricanes, floods, droughts and wildfires are becoming more extreme, and can be directly linked to climate change. Hundreds of millions of people are impacted by these events every year. They have to leave their homes or relocate to safer areas during a storm, struggle to find fresh drinking water in a drought, or suffer from respiratory illnesses caused by wildfire smoke.

These changes are not inevitable, but they will get worse unless we take action. Thousands of scientists have agreed that limiting the global temperature increase to 1.5 degrees Celsius will help avoid the worst impacts and maintain a safe and sustainable Earth. But that won’t be easy.

Many of Earth’s ecosystems are vulnerable to rapid changes, and some species may disappear completely. For example, coral reefs are being harmed by pollution and bleaching, and Arctic ecosystems are warming at twice the speed of the global average. Glaciers and ice sheets are shrinking and melting, and rivers and lakes are breaking up earlier.

Climate change has also impacted agriculture, making some crops less productive, and forcing farmers to move to different areas. It has shifted animal and plant geographic ranges, and some forests are turning into deserts.

All of us are affected by climate change, but the effects will be felt differently by each of us. The people most impacted will be those who contributed least to the problem and who are unable to protect themselves, such as the world’s poorest nations and low-income communities. They have the fewest resources to respond and adapt, and are most closely dependent on a healthy, thriving natural world for their food and income. They need a three-to-six times higher level of financial support to reduce their emissions and switch to non-polluting energy sources.