I'd have to research the situation in Canaan more, but I believe that the Sahara was wetter until about 3500 BC, when it started to dry up. As I understand it, this affected the dawn of Egyptian civilization. Desertification still affects a lot of areas along the south edge of the Sahara.
Likewise, I understand ancient Greece was a lot greener, and human activity has played a role in drying it out. I understand human activity was a factor in the Dust Bowl in the US in the 1930s. The rising sea levels covered the Dogger Banks east of England within the past 10,000 years.
I recognize that climate change is way overhyped now, with global warming and all, but that doesn't mean it has never affected peoples or areas historically. I would take this article with a grain of salt based on my approach to filtering Wikipedia for bias, but I am willing to believe climate change may have played some role in the history of Canaan around that time.