Still a skeptic

My friend and debate partner replied to my post from yesterday on global warming. He wrote:

"...the sun activity is at a maximum and is about to drop. The global temperature of the earth is about to plummet – at a time when the hysterical (their word) world is preparing for rapid temperature rise."

Uh... I'd expect the sun's relative cooling to happen slowly, so earth temperatures are unlikely to "plummet". Also, I have not heard of this sun-about-to-cool claim anywhere else; I am skeptical of it.

The word "plummet" may not be the best, though it still might be appropriate when considering climate timescales. The claim was that our world will be significantly cooler by 2030. They compared it to the winter of 1658 when Sweden's army marched across a frozen strait and captured Copenhagen. This was at the coldest of the Little Ice Age.

As for that "sun-about-to-cool" claim, I hadn't heard it before either. Is it true? Those making the claim say this is part of the sun's various cycles in energy fluctuation coming together. They also say climate on earth is much more sensitive (high correlation) to energy from the sun. And climate is insensitive (low correlation) to the amount of greenhouse gasses in the atmosphere.

Skeptical of it? Good.

My friend continues:

Even if Kooistra had offered a case that temperature measurements were systematically wrong, I did not imply nor mean that all evidence for global warming is thereby invalidated.

This is one of the points Stan Schmidt, Editor of Analog Science Fiction and Fact made in his rebuttal to Kooistra, though I didn't mention it yesterday. Some bad data, when there is a great deal of other good data, does not invalidate the premise.

As we know, the global science community is overwhelmingly united in support of global climate change and presents broad evidence for it.

Indeed, they are and do. Yes, there is lots of evidence that the climate has become warmer over perhaps the last century. There is also lots of evidence that there has been a great increase in CO2 and other greenhouse gasses since the start of the Industrial Revolution. For about a century the correlation of the two has been high. But the research I linked to yesterday prompts the important question: Did all those climate scientists confuse correlation with causation? These researchers found much better correlation over a longer period of time between climate and sun energy levels.

So will the correlation between global temperature and increasing greenhouse gasses continue as the sun's energy drops?

I'll rephrase my concluding point from yesterday. I can't tell which of these competing scenarios is correct. Perhaps I should be skeptical of both. But there are other reasons, mostly pollution, to reduce carbon emissions. I support the agreements that recently came out of Paris, even if the science behind it might be wrong.