https://www.theglobeandmail.com/report-on-business/breakthro...
There're still a lot of practical problems with the Northwest Passage - notably, the most direct routes are too shallow, there remain lots of icebergs and ice sheets, it's not well-mapped, and there are few resupply ports along the way. I'm not sure I'd agree with all the criticisms in the article (notably, they assume the Northwest Passage will always have ice in winter, but in many "greenhouse earth" scenarios the arctic is ice-free year-round), but it's decades out, not years.
https://www.nature.com/articles/nclimate3004
According to the above (2016) Nature article, 25% to 50% of the globe shows greening, with only 4% showing browning.
Additionally if the greening is occurring in previously permafrost soils that are not very useful for farming then there is not an increase in the food produced by that green area.
https://apps.fas.usda.gov/psdonline/circulars/production.pdf
It's glacial maximums that are really concerning to me personally. It's very unlikely that we could feed so many billions of people as we do now if we ever enter another ice age.