without intruduction & conclusion, the main part:
The most to conceder is the increase of seawater level.
Most of the coastal cities will be in danger and some countries may completely disappear. Al that because the increasing in temperature is going to melt the ice in the South and North Pole.
Another problem is climate changing. Temperature changing will affect the climate in many ways. There will be more storms, floods and unusual rain seasons and some places is going to suffer from dryness.
One way to save climate is by reduce using oil which produce a lot of carbon dioxide one of the green house gases and the main reason of global warming and depend more on the renewable energy like solar and wind energy.
One more solution is to use less energy or electricity. By using less electricity, less oil and recourses are going to used and less carbon dioxide is produced.