In light of the recent climate strikes and all of the associated discussion, I would like to remind people that anyone who says that current global warming patterns are a natural part of the earth’s cycle are either uneducated or are lying.
image source. This is a graph showing the global mean temperature for the past 20 000 years, as well as predicted temperatures up to 2100.
(IMPORTANT: 0*C represents the mean for last 30 years. Temperature anomaly indicates deviation from that norm)
Yes. Global Temperatures from ~8 000 to 2 000 BC were warmer than in the last century. HOWEVER. The rate at which the climate warmed to those temperatures was much slower. The rate. That is a major problem. See, the earth has been heating and cooling over and over for several million years now. Populations of organisms adjust to this by either evolving or changing their ranges and/or behaviour. We typically observe changing fossil assemblages of organisms at different time periods in the same site. This shows that organisms move around to maintain their niches.
Currently though, the climate is warming too fast for organisms to adapt. Within the lifetime of a Maple tree, the climate will warm by as much as it has in the past 20 000 years. That is absurd. That is not enough time for the planet’s ecosystems to adjust to changing temperatures by moving up mountains or poleward. Combined with fragmented habitats and straight-up habitat loss, this spells disaster for life on our planet.
The extreme speed at which our planet is warming is unprecedented. As in, never done or known before. Well, I suppose a certain asteroid may contest that, but to any who suggest global ecological collapse just justified because an asteroid did it first can go feed themselves to the sharks.