I keep hearing the argument from people that "the earth has gone through cycles like this before" and while that may be, humanity hasn't experienced that before.
I'd venture that putting pavement all over the earth's surface, chopping down forests, turning all of the earth's surface into farm land, etc has done far more harm to other wildlife on earth. Humans are simply destroying everything in our path. A few degrees temperature change in the next 100 years is really fairly mild compared to everything else we're doing to mess with and destroy animals' habitats. This habitat destruction has happened far more rapidly, and there is absolutely zero political will to stop or reverse it as well.
Does it matter if it's man-made?
Yes. Most efforts are aimed at reducing man-made climate change by imposing onerous conditions on the populace. If our fossil fuel use hasn't hurt, then cutting our fossil fuels won't help.
If our fossil fuel use hasn't hurt, then cutting our fossil fuels won't help.
CO2 and methane are known greenhouse gases. Reducing them in the atmosphere will lower warming even if humanity not the main factor in climate change.
It does matter though. The paper claims human CO2 is responsible for 0.01C warming. If that is the case, reducing our CO2 can make a maximum cooling impact of 0.01C which is entirely unimportant.
Of course who knows if these numbers are true or not, but the point is it could matter, and our CO2 could be unimportant in magnitude compared to other processes (which is what the paper argues).
Does it matter if it's man-made? It's more or less known what heats or cools earth, and a fast change isn't good for most species and areas.