As a geographer and historian double major I feel some ability to answer this, finally!

Unlikely is my answer. Climate systems have a lot of inertia and require a lot of time or energy to get moving and a lot to get it changed, like we're only get the effects of climate change hitting now and the impacts of our actions now won't hit for quite a while. So that timeline with the proposed reasons is probably too short and there isn't enough grunt in the changes of forestation to cause this.

The most compelling answer I have received from a climate-geographer was a shrug. A lot of little things probably came together and it just happened. Climate change and the like is so widely complex so trying to link cause to effect is a right royal bitch without a mental amount of data and modelling. Currently the climate science we have utilises both crazy good modelling (we think) and huge amounts of data but even then finer predictions of what will happen from accelerated climate change is hazy as one change will impact something else which will impact on something else. I only add that last bit just to highlight the complexity.

Not based on one specific research paper but the gathered understanding of four year of geographical study at uni and linking with history study and presented to you in a poorly formatted-late at night-end of a teaching week-paragraph.

I'll happily expand on things tomorrow if anyone has questions.