The Karl et al. study highlights something I've been thinking about lately. I don't know if the Karl paper is important, good, or bad. It claims to debunk the slowdown in surface warming. Other papers will claim the opposite. This won't be the end of it, but imagine that it was – imagine that we saw a decisive breakthrough in climate science, or a series of them, that debunked the slowdown, and another body of work that settled on 3.1 °C for ECS.
If you're a climate skeptic, or better yet, a person who is currently skeptical of burdensome future human-caused warming, you should be ready not to be.
You're presumably skeptical because of issues you see with the evidence, levels of certainty or uncertainty, perhaps features of climate science and its methods or predictive track record.
All of those issues can in theory be resolved by new evidence, or new types of evidence and methods.
If you're a skeptic or a lukewarmer I wouldn't assume that the evidence is going to roll your way. (ECS seems to have had a bit of a downward run over the last few years, but who knows.)
You should be ready for anything, evidence-wise. Don't get too comfortable. Life is full of surprises, and so is nature. Earth's climate answers to no one. It will do whatever it does. It is completely uncoupled from our desires, agendas, elections, ideologies, beliefs, arguments, pride, etc.
I don't think people should hitch their ideological wagons to the behavior of a planetary climate system. That's odd. This applies to everyone of course.
1. Measuring surface temperatures sure is complicated. In fact, as Gavin Schmidt said, global mean temperature isn't measured per se. It's estimated. Scientists can come along in 2015 and redo the temperature estimates for the past several decades. That's strange. Most sciences don't work that way, don't have this constant process of re-estimation of past measured variables. If scientists can redo temperature estimates in 2015, they can presumably redo them in 2016, and 2017, and perhaps in 2023. I think we need to understand this better. Maybe they're closing in on maximum feasible bias reduction and we won't see much adjustment in the future, but this should be explained.
2. Knowing about or believing in human-caused climate change is nothing like knowing about gravity or that the earth is not flat. This is not like looking at something and seeing that it's there, or figuring out the horizon, or dropping a ball. It's so much more complicated, driven by inferential estimates and wicked statistics. Climate activists should be much less mean to skeptics, and stop trying to treat this issue as though people are obligated to march to the claims of a young, complex, and revisionist science. I don't think people are obligated to believe in things they cannot observe or confirm directly except in special circumstances. Believing in everything the media folds under "science" is probably unwise, and it's unclear how a rational knower is supposed to navigate our media/science culture. I don't have any kind of prescription.
The eternal caveat applies: The science is just the science. It doesn't have to matter to you, not politically, not philosophically or personally. People get to choose their political philosophies and ethical systems, and you don't need to catastrophize any arbitrary level of future adversity if you don't want to. You don't have to care about the science of obesity, or the science of testicular cancer, or the science of sadness, or an increase in storm count. There are lots of things a person could choose to care about or not care about, and it's unclear why anyone has to care about any particular science or diffuse future risks.
There's a mindset in modern politics that wants to "Do Something!" about everything. I think we'll find that some of it is driven by affluence – that people worry about more things, smaller things, the more affluent a society becomes. In any case a person's quality of life is powerfully shaped by their perspective and framing – we know how profound that can be, the glass half full vs. half empty mindset. It's strange that we never seem to apply that wisdom to environmental issues. You could put me on the gulf coast and jack up the hurricane count by a third, and I wouldn't care if I had someone to love and books to read. There are so many other things going on in a human life than weather and sea levels, so much more beyond material and economic concerns. Some people (not me) would move to Mars if they had a chance, even though the climate would be so hostile that they'd be confined to quarters.
That's not just about affluent American space geeks – most people in the world don't care about climate change, even when forced to choose six "priorities" in a biased UN survey. The UN wouldn't let me participate in the survey because I couldn't find six things on their list that were priorities to me. The list is framed from a top-down, government-centric bias that enjoins people to express vague wishes for "better" roads, health care, food, and so forth. They don't offer priorities like "end the drug war", "deregulate immigration", "cut taxes", "eliminate income taxes", "free market healthcare", or "get the UN out of my life." It was designed for the UN to be able to say that adults around the world want governments to deliver things like "affordable and nutritious food" and "action on climate change". The items and forced choices will systematically discriminate against non-leftist participants, as well as people who don't think there are lots of problems they need authority figures to solve – such people won't even be allowed to submit their answers. The stated goal of the survey is "that global leaders can be informed as they begin the process of defining the new development agenda for the world", what economist William Easterly would call the "Tyranny of Experts". And still, even with the rigged design, people don't choose climate change.
Relatedly, Bjorn Lomborg was correct to say that Pacific Islanders don't care about it. (Choose Oceania in the dropdown.) Pretty much no one does. It doesn't make the cut on any continent or region that they list. As for affluence, start with the Low HDI countries option and work your way up – the poorest countries care the least. As per my hypothesis above, more people care as you work up HDI, yet it never makes the cut even in the richest. I didn't know that until today. I thought environmentalism was more popular than this, but I now realize that I probably just know a lot of environmentalists.