Is the Sahara shrinking

Answer 1

The size of the Sahara is always slightly changing over shorter periods of time (decades and centuries), but also dramatically changing over very long periods of time (thousands and tens of thousands of years).

Throughout recent earth history, the Sahara has been flip-floping often between being a desert and being woodland. As recent as 10,000 years ago, there hardly was any desert in Africa and the area was full of lakes and rivers and water reservoirs. Until almost 80,000 years ago it had been a desert like today. And before that it had much less desert than that most of the time.

Because of all those fluctuations, both on the short term and long term, you can't really plot any clear trend on it.

In the 70s and 80s there were periods of unusually long and harsh droughts, which made the Sahara expand considerably. No one really knows for sure why this happened. Just like predicting the weather, the reasons are often too complex and random to follow. Because those droughts scewed the tip of our data at the time, in the 80s and 90s people have tried to claim that the Sahara has been on an expansion trend in the last 100 years. And they tried to blame climate change for it.

But new data shows, that the Sahara has been shrinking since then at a fast pace. People now rather try to argue, that it could actually be shrinking due to climate change and that it even started disappearing again on the very long run. This is, amongst a lot of other things, because climate change produces stronger monsoons which is the only major source of rainfall in the Sahara region. More CO2 in the atmosphere also acts as a fertilizer. The historic data supports a correlation with CO2 somewhat.

If you want to know more about it you can read this paper:

sciencedirect [dot] com/science/article/pii/S2590332220301007