According to some predictions, climate change will cause up to 3 billion refugees by the end of the century.

Those are some very optimistic predictions.

Here are some fun links from the World Economic Forum and the United Nations: Global freshwater demand will exceed supply 40% by 2030 and 90% of global top soil and arable land is at risk of depletion by 2050.

And to add to all this, the ice caps will likely be melted completely in the next decade causing the Blue Ocean Event, where massive amounts of previously reflected solar radiation will instead be absorbed by the oceans, causing the release of huge amounts of methane from the sea bed and the earth to cook in it's own atmosphere.

This is a good explanation for anyone interested in further reading on the BOE. Look this up for yourselves with other sources though.
(You'll want to find out how much ice coverage is left at the poles, how much we've lost this year so far, and the loss projection for if the next 5 years are as hot as 2023. Then look up what will happen to the earth with all the unreflected solar radiation we'll be absorbing without the ice caps).

Billions of people are going to die in the next 30 years due to climate collapse. There may not be 3 billion of us left to be clinate refugees by the end of the century.