The chance of staying below two degrees: INDCs and the Seven Ifs

There is an easy-to-follow video published by Climate Interactive titled How Could Paris Climate Talks Ratchet Up To Success? It runs quickly through a series a of what-if scenarios to calculate what the effects of various emissions promises could have on global temperatures to 2100. It starts with the Intended Nationally Determined Contributions (INDCs) pledged for the Paris COP, which in many cases only have targets up to 2030, and  extends them using various assumption out to 2100.

The numbers are based on the C-ROADS model, described here.

The presenter, Andrew Jones, shows how we can go from business-as-usual emissions to get to a fifty-fifty chance of staying below two degrees Celsius.  There are a lot of “ifs” along the way, I counted seven. You could easily count more. I assume that the expected warming for various scenarios is the median value, 50/50, derived from climate models. Continue reading

NASA October temperature update: a new monthly record

Wow. Just in time for Paris.

My guesswork now looks a little lame as the Nasa October land-ocean temperature anomaly shoots upwards to a new record of 1.04 degrees Celsius.


Monthly anomalies for selected hot years since 1998. My guesswork forecasts are shown in dashed and dotted lines. Data from NASA.

A clear all-time temperature record for 2015 is now assured, because November and December anomalies would now have to be less than 0.34 degrees, a level not seen for those months since 2000, for 2014 to retain the warmest year record.

My original anomaly forecast for the year was 0.82 degrees C , which is unchanged below, but is clearly now conservative and is shown  by the red square. The red cross (0.86 degrees C) is a projection based on November and December averaging the same anomaly as October.2015-11-16_17-41-51

As Michael Caine put it: Continue reading

Not all Christians are like Roy Spencer, thank God

Dr Roy Spencer of the University of Alabama is one of the few scientists who minimize the importance of the human contribution to recent climate change. He is also an ardent Christian and a member of the advisory board of the  Cornwall Alliance, a group that thinks that God’s fingers control the global thermostat. He’s an evolution “doubter”, “contrarian” or “skeptic”, as well.

Previously, he  has likened those of us who are concerned about climate change to Nazis.

Today, in the wake of the dreadful terrorist attacks in Paris, he posted this on Facebook.

As a response from a Christian to the human suffering in Paris, I would have expected something better than sarcasm and ideological point-scoring. You know, something like compassion for the victims, even forgiveness for the perpetrators. Instead Spencer serves up snarky comments about SUVs and gun control. He should be ashamed of himself.

However, we must be careful not to judge all Christians by the behaviour of one deranged extremist.

So long, Keystone XL

After an approval process that lasted longer than World War Two, President Obama finally said “No” to the Keystone XL pipeline.

This is undoubtedly a major victory for climate activists who had a lot staked on the outcome. Obviously, this is a defeat for the oil sands industry, but it is also something of a blow to the Serious People who are in favour of action on climate, but who consider protesting against the construction of infrastructure to be naïve at best and, at worst, a counterproductive distraction from the real action of international negotiations and policy wonkery.

If you haven’t done so already, read David Roberts who writes most of what I’m going to, but does it better.

What the Serious People say

  • One pipeline is not going to make much difference to global emissions.
  • Oil sands’ emissions have been overstated.
  • Coal.
  • What matters is reducing demand, not restricting supply.
  • There are transportation alternatives to pipelines, like railways, and they are more environmentally risky.
  • It’s a distraction.

This is all true, more or less. But it is also beside the point. Continue reading

Consensus on plate tectonics and climate science



From Cook et al. 2013

One of the surprises I had when I was involved in the Cook et al (2013) paper was how many abstracts there were that hardly mentioned anthropogenic global warming. This was despite them having been selected using the key words global climate change and global warming.  When we got to the stage of tabulating and plotting the ratings over the 1991-2011 period, what was even more surprising, to me, was that the proportion of abstracts that took No Position (NP) actually rose from about 50% in the early 1990s to about 65% in 2002, after which that proportion stayed more or less the same for nine years. It wasn’t immediately obvious to me how this squared with the increasing knowledge and generally reduced uncertainties expressed in successive IPCC reports.


From Cook et al. 2013

The other investigation we did was to ask the authors of the articles to rate their papers on the same scale. Here the overall percentage of NP was lower, about 35%. Not all authors responded to our email queries, so the sample size is smaller than for the abstracts. Also, it was harder to track down email addresses for researchers in the early 1990s, so the sample is particularly small then. Nevertheless, the rising proportion of NP papers is if anything a little more marked here, rising from around 20% in the 1994-1999 period to around 35-40% in the 2001-2011 period.

The difference between abstract and paper NP proportions is not surprising: the abstracts are reserved for key results and the available space there tends not to be wasted telling everyone what the prevailing paradigm is. Also, as confidence in the paradigm grows over time, a larger proportion of  papers might consider the attribution of global warming to be an established fact and not something that needs to be endorsed even in the body of the paper itself.

We might well expect to see the same thing in other subjects: for example, life scientists no longer need to affirm evolution through natural selection, it has become settled science; geologists take plate tectonics for granted today, although they would not have in the 1960s when there was a scientific revolution underway. Rising NP proportions in climate science papers, contrary to intuition, might well signify rising confidence among researchers that human emissions are a main cause of global warming—something that just does not have to be reaffirmed every time the subject of changing modern climates is discussed. Continue reading