It’s been a few months since I’ve kept track of my bet to no one in particular that 2010 would be the hottest recorded year. With the conclusion of the Cancun climate meetings proving fruitless and NASA releasing data for November, it’s time to see how I did.
To briefly recap, in fall 2009 I started to tell people that I believed there was a 99.9% chance that we’d see at least one new hottest year before 2013, with a 75% chance that 2010 would set a new record. Based on the recently released data for November, this is almost guaranteed to happen.
My reasoning was fairly simple. In 2008 we had nearly every known short term cooling factor in full force: there was a large La Nina, decadal oscillation was providing a good amount of cooling and the solar minimum was a century low. When I made the prediction it was apparent that those cooling factors had started to reverse and would the warming phase would peak sometime around 2012. It was unclear when they would peak or how fast they would accelerate, but it was an easy bet to make. I remember telling someone “as long as there is a moderately large El Nino in 2010 then predicting that will set a new record is almost like taking candy from a baby.” Indeed, by November 2009 it looked like an El Nino event was forming that was going to be at least as large as normal, so I felt confident and it looks like I was proven correct.
Now how well did my assumptions play out?
- Will first of all, even at the time I made the caveat that if there was a major volcano eruption then the bet was off. When the Icelandic volcano started to erupt (with fears of its much larger neighbor erupting as well) I felt glad that I had remembered to add that caveat. It’s possible that the volcano caused some cooling, as the temperature anomaly was lower this summer, but I’m not sure about its total effect. It may have made it cooler than I was counting on. [Although probably not.]
- When it came to solar activity, it did start increasing from the minimum but the onset has been slower than anticipated. In general this would have made it slightly cooler than I was counting on.
- The biggest surprise by far was the rapid decline of El Nino into a moderate La Nina event. I was caught completely surprised by that, and around August thought there was a strong chance that the rest of the year would fall in anomaly quite a bit. That La Nina is still in force but somehow we just set a record for November. This effect was strongly cooler than I anticipated. In fact looking at the NASA graphs, you can’t even tell this was an El Nino year anymore.
- The Pacific Decadal Oscillation continued the reversal from its low back to a neutral range, which is in line with what I was expecting.
There are a few other oscillatory effects, but it is my understanding that these are the main ones to focus on. Therefore, I conclude that even though I was correct about 2010 being the warmest year, it was warmer for a reason that I didn’t anticipate. Now there are a few possibilities for this. There is always going to be random noise that can’t be predicted and we may have just happened to hit a higher level of warming due to that. Another possibility is that there is an observed by not well understood mechanism for heat transfer between the ocean and atmosphere. It is basic physics that as the ocean warms it will be unable to hold in increased energy effectively, but there is growing evidence that it does so in a dynamic process based on interactions with the ocean depths. The data about this is relatively old (last data point I’ve seen is 2005) but it’s possible that we got some “extra” heating that had been stored from prior in the decade and is being released now. Another possibility is that increased CO2 levels have made us more sensitive to the increase in solar activity to the point that it has more of an effect than I predicted. Yet another possibility with increasing data support is that some of the climate positive feedbacks like permafrost methane release, decreased Arctic ice leading to more heat absorption, etc. are starting to be felt more strongly.
Whatever the reason, Jim Hansen has been talking about 2012-2013 as being the years that end the climate debate for good because we should be at another solar maximum by then [assuming we're not at a paradigm changing atypical spot], and combined with an El Nino will absolutely demolish temperature records. It will remain to be seen if Hansen is absolutely correct, but the point of this exercise is that I strongly believe that our understanding is now qualitatively strong enough to a) make predictions like I have and b) use the model to look for unexplained phenomenon that cause a deviation from CO2 based forcing. The message that there hasn’t been warming since 1998 (or even cooling) is not only wrong from a proper data analysis perspective because you should average at a timescale that sufficiently takes care of noise and dominant oscillations (look at the difference between the 5 year mean around 1998 and the past decade) but the framework of understanding perfectly explains why 1998 was so abnormally hot (look at how massive the El Nino was) and why temperatures fell a bit in 2007-2008, creating the appearance of flattening (the La Nina combined with solar minimum). The collection of climate hypotheses are being strongly supported by data and showing that scientists have a strong grasp on short-medium term climate dynamics, and should be recognized as such. Yeah something may happen that invalidates our understanding, but that’s the basic premise of science, and hope is no way to make decisions.
Finally, it is a valid criticism to say that I have addressed shorter term climate metrics and not the longer term feedbacks that lead to runaway warming [although our current pace is already starting to cause a lot of problems] in the coming decades. While that is true, I would note that not only has every long term positive feedback been observed over the last few years, but it has been occurring faster than the assumptions in the models. Hence the models are too conservative unless there is a HUGE negative feedback dynamic that no one has even thought of. With the possibility of increased cloud generation acting as a major negative feedback shown to be highly unlikely, there is no proposed dynamic that I can think of that could be true and lead to the temperatures we are seeing. Due to the nature of complex systems it’s possible one could pop up at any second, but that would be sheer luck.
While there are honest disagreements about how to accomplish the goal, it is imperative that CO2 reductions be seen as the primary consideration in political and industrial decisions about long term planning. The window for doing so is fast closing, not only due to current CO2 emission paths, but the increasing evidence that peak oil is upon us — an event that will cause huge upheaval and pressure to make CO2 emissions explode through indiscriminate usage of coal and poorly constructed natural gas wells (which have as bad emissions as oil). There is no rational basis for refusing to take action, especially since even moderate warming scenarios will cause far more economic damage than drastic mitigation plans. It is unconscionable that this has fallen off the press radar and has become entirely partisan.