While Covid-19 has shaken much of human society, the threat posed by global warming has not gone away. Click here to read the full BBC guide.

Human activities have increased carbon dioxide emissions, driving up temperatures. Extreme weather and melting polar ice are among the possible effects.

What is climate change?

The Earth's average temperature is about 15C but has been much higher and lower in the past.

There are natural fluctuations in the climate but scientists say temperatures are now rising faster than at many other times.

This is linked to the greenhouse effect, which describes how the Earth's atmosphere traps some of the Sun's energy.

Scientists believe we are adding to the natural greenhouse effect, with gases released from industry and agriculture trapping more energy and increasing the temperature.

This is known as climate change or global warming.

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