Is global warming speeding up?
Or more to the point, is the rate of warming greater than current science currently says?
Is global warming speeding up?
There has been some discussion about this recently. For some, if you look at the changes in global surface temperature, it seems like the rate of warming has increased. For others, an apparent uptick in rate of warming is just a normal short term shift in the rate of warming that is offset by prior and future downturns in rate. Regardless of whether there is a change in rate of warming, the question itself brings up a number of sub-questions of interest. Some of these questions are about climate science, some are about how to wrangle and interpret data, and some are about the rhetorical interface between science and the public conversation.
I have some thoughts.
First, on the rhetoric. Never mind the science for a minute. There might be a problem if climate scientists and their helpful surrogates start talking about an acceleration when a few years ago we did a lot of yammering about how there was no pause — a phenomenon being claimed by climate denialists — so stop talking about a pause. If we can have our acceleration now, why couldn’t climate change deniers have their pause back then?
This rhetorical problem may seem unimportant and weak, but I assure you: The average Mainstream Media reporter will use exactly this logic in shaping what they say about climate change, should they get wind of this debate to begin with. Beyond noting that this is a thing, I don’t have much else to say about it.
Regarding the climate science itself: I have two ways of coming to conclusions regarding developing climate science. One is to read the peer reviewed literature, published or posted, commentary or whatever, etc. about the issue and come to some conclusion. Sometimes this involves interviews or emails with some scientists. This works in certain areas of climate science where, as a scientist who has done some (mainly paleo) climate, I actually understand things at sufficient level of detail, but it does not work where I’m out of my own ballpark. The question of change in rate includes elements where I’m distinctly out of my ballpark (modeling) and others where I’m comfortable (understanding variation in the data).
The second method I use to get a bead on climate science is to see what certain experts, who tend to be right most of the time, are saying. I know what you are thinking. A true analyzer of information will come to their own conclusions and not base anything on what others say. If you are thinking that, you may need to rethink how you think science works. Scientific thinking is always a combination of direct observation and analysis of data, understanding and taking at face value the work of others, and trusting in certain contextual information (often “basic facts”) that you, yourself, did not think of and couldn’t necessarily reconstruct or rediscover because you don’t have the training, equipment, or funding. So you just find out what the current thinking is and go with that.
Unfortunately, in this case, two of the people whose opinion I tend to follow when I’m not sure which direction I want to veer towards have different opinions. Michael Mann is saying: no, no acceleration; in contrast Gavin Schmidt is saying; hey look, there seems to be acceleration. I tend to believe Mann’s argument because it relies on deep thinking about the modeling, but Schmidt makes valid points about the data itself. So what do I do???
Perhaps we are looking through a foggy window onto deep thinking about the science of climate itself, which is mainly about modeling climate and then seeing what the heck the climate actually does. In this area, Mann is convinced that the current modeling works well to characterize the relationship between atmospheric CO2 and global warming. He is not saying that we couldn’t have an acceleration of warming, or a deceleration, if we increase or decrease atmospheric CO2, with changes in our behavior. In fact, he is saying that we can and should do that. (Should decrease. Obviously.) I think Mann is claiming that variations around a mean trajectory are due to normal inside the system variation, and not some change in the nature of the Earth’s climate system or its relationship to atmospheric CO2.
Schmidt’s view looks different but actually is not. I noted above that Mann would say there is a well understood link between CO2 in the atmosphere and global surface temperatures. I lied. It is actually a little more complicated then that (I lied again, it is a lot more complicated). And one of those complications is the stuff in the atmosphere off of which a certain amount of energy from the sun bounces, thus not contributing to surface warming.
Schmidt notes that there is research indicating that staring in “…. 2020, new regulations required the shipping industry to use cleaner fuels that reduce sulfur emissions.” This may have increased the role of the Sun’s energy in warming the Earth’s surface. However, he notes that the data required to test this hypothesis are not yet available, and if this is a factors, it may not be enough to account for what he sees in the data (note that Schmidt’ team is responsible for one of the main data sets used in this sort of analysis).
I tend to side with Mann in suggesting that the current modeling methods provide an increasingly accurate picture of warming, and that observed fluctuations around a mean are within expected parameters. But I also agree with Schmidt when he notes two things: 1) super good data such as we have in the current era of satellites has only been collected for a few decades, so there may be insufficient information in some areas of modeling; and 1) the basic nature of the climate system chan shift in ways we don’t fully understand and cause some of our models to break. I don’ think that has happened yet, but it has probably happened before and will likely happen again.
Regardless, we need to stop polluting the atmosphere with the effluence of our insane tendency to set everything on fire. Stop the burning. Electrify everything, and decarbonize electricity.