This isn’t about local ecosystem disruption. It’s about releasing more global warming gasses into the atmosphere than humans have produced since the start of the industrial revolution.
http://www.futureearth.org/blog/2018-jan-31/how-much-carbon-...
> Trees and other vegetation are the planet’s carbon storage closet – absorbing and releasing carbon dioxide and other greenhouse gases in an ongoing cycle. But just how big is that potential? A study from December has calculated that the world’s vegetation, from Amazonian rainforests to Eurasian grasslands, may hold about 450 billion tonnes of carbon today.
https://www.co2.earth/global-co2-emissions
> From 1870 to 2014, cumulative carbon emissions totaled about 545 GtC. Emissions were partitioned among the atmosphere (approx. 230 GtC or 42%), ocean (approx. 155 GtC or 28%) and the land (approx. 160 GtC or 29%).
This is my optimistic take! :D