It is believed
may affect climate.

global warming

Explanation:

The global warming is believed to be able to affect the global climate through warming it up. It is mostly the emissions of greenhouse gasses that are considered to be responsible for it, such as the carbon dioxide and methane, but in reality it is the natural factors that have the leading role by far.

The releasing of these gasses into the atmosphere by the humans since the Industrial Revolution has caused rise in the amount of these gasses into the atmosphere, rise that is more rapid than the natural increase of it. The world has been in panic lately as it has been noticed that the global temperatures are on the rise, and that it may have catastrophic consequences for the humanity.

In practice though, it turned out that only one of the projections about the climate changes was accurate, that being the Russian model, which was also the least dramatic one, while all the other models were predicting dramatic changes, but that didn't happened. Also, the panic about the catastrophic effects of it are also way to exaggerated, as a global warming, as the geologic evidence shows, will actually make the climate much more equalized, with the extremes in temperatures largely minimized, and having much more wet and green planet. The only real problem is that big portion of the human population will need to be relocated on slightly higher ground as the sea levels will rise.