Just want to give people a little foundation for understanding climate. The big claim right now is that rising CO2 levels are creating runaway higher temperatures and will have us all living either in deserts or under the expanding seas. Just to be very upfront about my bias, this is all bullshit driven by ideologues who as usual, have corrupted the science in favor of what they believe.
Temperatures more than 150 or 200 years ago largely are inferred from proxies, since there were not reliable thermometer records. Even the recent thermometer records have been corrupted by supposed necessary adjustments which inevitably and mysteriously always seem to make the past cooler and the present warmer than the actual readings show. A proxy is some measurement from which temperature can supposedly be inferred–tree rings are a notable one. The best record for guessing at, and honestly, that is what it is, long-ago temperature are ice cores, and the longest of those come from Antarctica, where we can see several glacial cycles.
These two charts show a fairly long record of the earth’s average temperature and one just covering the last few thousand years. What is immediately apparent is that there is actually nothing unusual about the last few decades’ temps. In fact, the earth has been much warmer a number of times in the past. You can see that the current interglacial period in which we live is similar to the one two cycles ago, and that warmth hasn’t yet come close to the peak of the immediately past cycle.
On the more recent chart you can see that even within this interglacial cycle current temperatures are nothing to get alarmed about and have not reached other intracycle peaks. So keep these charts in mind when you see bullshit about “unprecedented” warmth. It simply isn’t true. And remember why the morons who espouse this nonsense do so–they are trying to control your lives.