Climate and cherries

In a recent blog post at Climate Lab Book a recent press release by the World Meteorological Organisation (WMO) describing recent global temperature changes were discussed. Ed Hawkins makes a point about the definitions of a decade (from 2001-2010, 2000-2009, etc.) alters the conclusion of the report. He finds the largest change in temperature between decades is not to the most recent decade as claimed by WMO, but from 1987-1996 to the average of 1997-2006, at +0.24K.

The definition of a decade is cultural, and the result of such analysis clearly is dependent. To explore his ideas further, we define a decade as having 85 different starting and ending points, but all covering a period of 120 months. This means the last decade can be defined as 1996.05.16-2006.05.16, 1996.06.16-2006.06.16, …, 2003.05.16-2013.05.16. This will give us a distribution for each decade and hence limiting the issue of decade definition.

Figure 1: Warming rate per decade



Figure 1 shows the warming rate between two decades, and it is evident the warming rate was greatest between 1990-2000 and 2000-2010. It is also evident the WMO statement “The decadal rate of increase in the global temperature accelerated between 1971 and 2010” is correct, but the picture is different if we expand the period to 1961 to 2010. The greatest change in warming rate happened from approximately the period (1970-1980/1960-1970) to (1980-1990/1970-1980), so I think we still see some cherry picking, with WMO and Climate Lab Book liking different cherries. Still, no doubt it is becoming warmer…

3 replies on “Climate and cherries”

Another bunch of cherrys on that graph might be the rather impressive accelerations in the warming rate seen around 1910s, 1920s and 1930s, cherrys that would be unfavoured by Ed, the WMO and you it would seem. One could also cherrypick the largest decelerations in the warming rate which seem to have occurred in the second half of the century rather than the first. there seem to be a cornucopia of cherries on that graph.

Yes. Warming rate was high in the 30s and 40s, but no *large* deceleration the last in the station based observational period. We might still see deceleration or no acceleration in some future decades (very likely), and (CMIP5) climate models might underpredict the frequency of such periods.

There is no doubt about the past warming and clioong of the earth. The ocean levels have gone up and down in response to more or less water locked in ice. We have been in a warm period for a long time, all of human history has been relatively warm The pace of climate change, as measured by ice cores, has been faster that ever before in the past 200 years, and that is how long man has been significantly changing the atmosphere by burning stuff. Climate is one of those sciences where you cannot go out and test your theories, because you can’t really manipulate a planet to experiment on it But you can use the evidence at hand, and i think we have done that well. The guy who mentioned dimming of the sun is also correct. Although we HAVE been in the fastest warming trend ever, we are also seeing a balancing effect right now from the sun, which is dimming, we don’t know why, or how long this will last, because we don’t fully understand the sun, and its cycles are sometimes longer than human history. We just have not seen this before.We don’t know if the earth will continue to heat up, or if it will start clioong down But we do know that global averages are a better indicator than local weather. Most people are experiencing local weather, and they say it is colder this winter than we remember’. These very people are forgetting the record highs last summer, and they are basing their beliefs about the whole world on what they know of their own spot on it. That would be like people from Arizona saying, “The whole world is a desrt! I can see it with my own eyes!”Finally, the reason people call you a cult member is because the role of information, good education and rational thinking has been eroded in our society. People consider their own opinion to be a better basis for truth’ than sober consideration of the evidence, or the opinions of experts. There is a lack of trust of established sources of information now, and of experts percieved as part of the system’. NOt just on this matter, but many others. We are not a rational nation, our leaders have been on TV, basing the truth’ they tell us on wishful thinking and/or fear instead of evidence for at least 20 years, and the people have lost trust, and so do the same.This has happened before in history during times of great national stress, and it will eventually change (we hope) as it has before. Stay rational, keep thinking. you do not have to agree with any one authority, but if you are considering the evidence YOU are a part of making things rational again. Keep it up

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