Last week, I wrote about how animals like the Arctic fox are being threatened by climate change. But it's not only animals that have been affected. Millions of humans around the world could also be forced to move due to global warming.
Already, about 25 million people have had to leave their homes because of environmental problems. The United Nations says this number could reach 150 million by 2050.
Many cities, like Hong Kong, are built near the sea. Here, we have mountains that rise far above the water, so we can easily build our houses on dry land. Many other cities are not so lucky, and they will be flooded if the sea levels rise.
Scientists predict sea levels will rise by as much as 60 centimetres in the next century as ice on the earth's northern and southern poles melts, and this water runs into the sea. That doesn't sound like a big increase in water levels, but it could still have a huge impact.
This is particularly true in Asia. Cities such as Guangzhou, Shanghai, Bangkok and Mumbai are all at risk if sea levels rise. Bangladesh and its capital city Dhaka are very vulnerable.
The saddest part is that the slums in the affected cities would be the first to be flooded. Poor people often live near beaches that are vulnerable to rising sea levels, beside garbage dumps where flooding would cause a huge pollution problem, or near railway tracks or on slopes that are prone to landslides.
