According to data released by NASA and NOAA this week, October 2012 was the 2nd and 4th warmest October’s (respectively) globally on record. NASA’s analysis produced the 2nd warmest October in its dataset; NOAA recorded the 4th warmest October in its dataset. The two agencies have slightly different analysis techniques, which in this case resulted in not only different temperature anomaly values but somewhat different rankings as well.
October’s global average temperatures were 0.69°C (1.24°F) above normal (1951-1980), according to NASA, as the following graphic shows. The warmest regions on Earth coincide with the locations where climate models have been projecting the most warmth to occur for years: high latitudes (especially within the Arctic Circle in July 2012). The past three months have a +0.63°C temperature anomaly. And the latest 12-month period (Nov 2011 – Oct 2012) had a +0.51°C temperature anomaly. The time series graph in the lower-right quadrant shows NASA’s 12-month running mean temperature index. The recent downturn (post-2010) is largely due to the latest La Niña event (see below for more) that recently ended. ENSO conditions returned to a neutral state. Therefore, the temperature trace (12-mo running mean) should track upward again, especially as cooler months fall off the running mean.
Figure 1. Global mean surface temperature anomaly maps and 12-month running mean time series through October 2012 from NASA.
According to NOAA, October’s global average temperatures were 0.63°C (1.13°F) above the 20th century mean of 14.0°C (57.2°F). NOAA’s global temperature anomaly map for October (duplicated below) reinforces the message: high latitudes continue to warm at a faster rate than the mid- or low-latitudes.
Figure 2. Global temperature anomaly map for October 2012 from NOAA.
The two different analyses’ importance is also shown by the preceding two figures. Despite differences in specific global temperature anomalies, both analyses picked up on the same temperature patterns and their relative strength.
The continued anomalous warmth over Siberia is especially worrisome due to the vast methane reserves locked into the tundra and under the seabed near the region. Methane is a stronger greenhouse gas than carbon dioxide over short time-frames (<100y),which is the leading cause of the warmth we’re now witnessing. As I discussed in the comments in post this summer, the warming signal from methane likely hasn’t been captured yet since the yearly natural variability and the CO2-caused warming signals are much stronger. It is likely that we will not detect the methane signal for many more years.
Of additional concern are the very warm conditions found over Greenland. Indeed, record warmth was observed at a 3200m altitude station in early July. 3.6°C may not sound that warm in July, but the station’s location at 10,500ft altitude is of interest. In contrast, continued warmth over portions of Greenland that have not witnessed such warmth did result in rapid melting during 2012. There was recent news that described how much faster melt has occurred over Greenland (see associated picture) than expected in the IPCC AR4. While the record-setting sea ice melt across the Arctic Ocean this year is important in some respects, at least melting sea ice doesn’t contribute to sea level rise. The opposite is true for Greenland melt: every drop that makes it to the ocean raises the level. When the melt is happening 3X faster than just 20 years ago, it’s time to pay attention (note: not panic!).
These observations are also worrisome for the following reason: the globe is experiencing ENSO-neutral conditions:
As the second time series graph (labeled NINO3.4) shows, the last La Niña event hit its highest (most negative) magnitude more than once between November 2011 and February 2012. Since then, SSTs peaked at +0.8 in September (y-axis). You can see the effect on global temperatures that the last La Niña had via this NASA time series. Both the sea surface temperature and land surface temperature time series decreased from 2009 to 2011. Note that the darker lines (running means) started to increase at the end of 2011, following the higher frequency monthly data. ENSO-nuetral conditions are expected to continue through the next 3-6 months, after which a new El Niño event might begin.
As the globe returns to ENSO-neutral conditions this winter, how will global temperatures respond? Remember that global temperatures typically trail ENSO conditions by 3-6 months: the recent tropical Pacific warming trend should therefore help boost global temperatures back to their most natural state (i.e., without an ENSO (La Niña) signal on top of it, although other important signals might also occur at any particular point in time).
So what do we do? I hope most readers are aware that the 18th Conference of Parties (COP-18) meeting is currently underway in Doha, Qatar. I’ve stated my opinion before that I don’t think putting every country in the world around the table to negotiate a climate treaty is the most appropriate approach. Canada, Russia, and Japan removed themselves from the Kyoto Protocol recently, which means that the only large emitters left are from the European Union. I actually think that’s more appropriate: I prefer regional and bilateral agreements – countries should have pursued them more aggressively in the past 30 years.
More to the point, we should focus on bottom-up approaches. There are smaller groups of people who, if provided the right type of expertise and resources when needed, could probably enact changes that will result in decreasing emissions as well as successful adaptation policies. The developed world is decarbonizing, but not fast enough yet. I also recommend you watch China. They invested very large sums of money in renewable energy and other green efforts. That money will bear fruit in the future. The rub, of course, is we cannot accurately predict when and how today. It will also be interesting to see how the northeast U.S. reacts to Hurricane Sandy. They have to rebuild infrastructure. Will they include adaptive measures while they’re at it or will they kick the can down the road?