How Warm Was May?

Human released greenhouse gas pollution continues to warm the surface of the planet. May was thought to be likely a very very warm month but it turns out to be merely very warm (only one "very") according to data released this morning.

Shockingly, May turned out to be, in the NASA GISS data set, less warm than expected. (I mainly get my cues for what to expect from my friend and colleague John Abraham, who has written up the May NASA GISS results HERE.) At the same time the May data came out (earlier today) the data for April was adjusted by NASA (these adjustments happen all the time, they are always small). So, May 2015 and April 2015 had the same anomaly value in the NASA GISS database, 71. That's in hundredths of a degree C, which itself doesn't mean much. The base period is 1951-1980, which is a time period after which considerable surface warming had already occurred. The lowest value in the top 20 warmest months since 1880 is 74, the highest 93, so May 2015 is not quite on that list but still warm compared to the baseline, which averages zero (because it is the baseline).

Using a 12 month moving average based on these data, we've had record or near record 12 month periods since some time in 2014. The present 12 month moving average is the fourth highest in the adjusted, updated data, but with all five of the highest periods occurring since the beginning of this year. Here's a graph of the 12 month moving average:


It is also interesting to look at the year to date. How warm is 2015 compared to previous years through May? Here's a graph of that too:


Either way you look at it, surface temperatures are rising. What does that mean? This.

Higher resolution graphics are available here.

More like this

Good grief. The whole range of the above graphs is about 1 degree C. Yet you show the planet on fire?

By Tom Harris (not verified) on 15 Jun 2015 #permalink

Tom, it takes a certain kind of person to think that the Earth is actually burning, that this isn't a graphic metaphor.

That would be you.

It also takes a certain kind of person to think that a degree C of warming across the globe's surface isn't much, because it is a lot

That would also be you.

Tom Harris,
Considering the amount of times that people have been explosed to your deliberate misinformation on the topic of climate change, it is ironic to see you here criticizing these same things.

Luckily here in Ottawa we have many well-informed and respected experts on climate change who have made sure to have their voices heard over your misinformation.

And yes I do mean this personally because I have no respect for a person who purposefully tried to mislead classrooms full of students. These people paid money to get an education and they certainly didn't get that while in your classes.

By Robert Way (not verified) on 15 Jun 2015 #permalink

Note how both Greg and Robert immediately try to shift the argument from whether depicting the Earth as being on fire is appropriate for a one degree warming (my point) to attacks on me personally. "Is your position so weak it cannot withstand rational debate?" ("Data", TNG). Looks like it, boys.

By Tom Harris (not verified) on 15 Jun 2015 #permalink

Tom Harris - if you feel small things can't have a big effect, then take 15 milligrams of strychnine and get back to me.

By Chris Kennedy (not verified) on 15 Jun 2015 #permalink

The thing about shameless people like Mr. Harris is that they're shameless. 24/7 -- seldom taking any time off. Ever.

By Andrew Skolnicki (not verified) on 15 Jun 2015 #permalink

will you post my response? If not, why not?

By Tom Harris (not verified) on 15 Jun 2015 #permalink

An elephant can crush a cockroach to demonstrate significant superiority when it comes to weighty matters...

But is it really necessary to do so to impress onlookers?

After all, they already know the outcome -- and surely have better thing to give their attention to anyway.

By Brainstorms (not verified) on 15 Jun 2015 #permalink

We can add Andrew Skolnicki to Greg and Robert as personal attackers. Any more?

By Tom Harris (not verified) on 15 Jun 2015 #permalink

whether depicting the Earth as being on fire is appropriate for a one degree warming

OK, so what is an appropriate graphic to point out that the earth's surface is undergoing warming which if it continues is very, very serious?

By Chris O'Neill (not verified) on 15 Jun 2015 #permalink

An appropriate graphic metaphor: Tom Harris' Pants on fire.

Hey Tom, ya got a graphic that shows a rich fat-cat paying hush money?

(Feel free to paste a JPG of yourself on the receiving end if that makes you feel honest.)

By Brainstorms (not verified) on 15 Jun 2015 #permalink

Tom Harris' comment is unbelievable.

The globe is a metaphor for an earth that is rapidly gaining in total net energy, changing its systems, its ocean heat, melting ice caps. (Now not just melting at both poles, but accelerating) and despite that STILL with enough excess energy left over to slowly but over time continually increase the overall ambient global surface temperatures.) With many regions changing a lot more, and a lot more quickly than the global averages, and lot more unpredictably.

And not only is there a fundamental reason for this - a remarkable geologic shift in long term molecular atmospheric energy recapture - it would be bizarre if it were not so changing.

Still, show this, don't be directly rude to him Greg. That doesn't help.

Also this presumption that Harris is shameless and know's he's lying is an incredible amount of presumption. This is partly why "skepticism" has taken such deep root. (It's not just because of "misinfo," as misinfo offers the gift of being incorrect and undermining its and its purveyors own credibility, if such is effectively shown past the choir, and what people know or think is NOT presumed.)

Please people who are concerned about ACC, stop presuming what everyone else really thinks, knows, or should know, how they think and what type of effect misinformation has on them - not to mention the self selection quality of news today, as well as the fact that often people are told "the earth" is warming" and "climate change" is a problem, without it being sufficiently shown and illuminated.

And stop presuming it is sufficiently shown simply because it is, to you, or you already know it.

It's not. Nor is what climate change "skepticism" is being sufficiently shown, or anywhere even close

And that's why near half the U.S. for example is deluded on the basic science and relevant facts applicable here, because the incredible misinformation and misconstruction of the Tom Harrises is not being effectively shown, while instead they are called names, dismissed, and it's presumed "no one listens" (to skeptics.)

Only the media and over 2/3 of the U.S. that doesn't think ACC is a major problem.

By John Carter (not verified) on 15 Jun 2015 #permalink

Tom Harris:

There's no reason Greg Laden should post or even consider your response. Your comments clearly come from a position of pre-determined advocacy, which is the opposite of science, whether, from these comments, you presumably teach it or not.

That advocacy, ironically, is the belief that a severe external geologic forcing - one that represents the equivalent of a now several multi million year shift in total long term molecular GWPe, in severely rapid geologic time - nevertheless wouldn't significantly effect earth's long term climate, despite the fact that climate already "change easily" and has changed before and in the long run is driven by net energy, which our earth's insulation has drastic and unavoidable influence over.

Not only does this belief not really make much sense, but there is not a shred of evidence, support or even any cogent, rational theory for it, and instead it relies upon misconstruing the basic processes of science itself - mistakes, alterations, adjustments, learning - for some sort of refutation of the climate change phenomenon itself. Which, apart from rhetoric, severe cherry picking, and often outright misrepresentation, is what all climate change "skepticism" relies upon.

It is complete and total faith based belief; whereas the dispassionate science suggests the likelihood of change, and the existence of a large and significant risk range, including the relevant possibility of fairly radical, unpredictable, and even at some point possibly rapid changes.

Skeptics however use rhetoric and the above referenced tactics to self convince (and convince others, and support misinformation on the topic) that they are in fact being "dispassionate" merely because some who are concerned about climate change sound a little worried, or use hyperbole on the subject - also irrelevant to the basic, objective, issue of ongoing atmospheric change and its earth impact phenomenon itself.

There is nothing dispassionate about thinking a geologically significant change to earth's insulation layer, and thus it's long term energy recapture, wouldn't ultimately significantly effect the expression of that energy. I.e, climate, as earth's systems adjust and change in response to an increase in energy, and accumulating energy.

It's belief, driven by desire, reinforced by misinformation, and fed by a conflation of the basic analytical framework, assessment and science of the issue, with the wholly separate issues of sensible redress and amelioration, and attendant economic connections and presumptions.

By John Carter (not verified) on 15 Jun 2015 #permalink

@ Tom Harris :

#7. looks like the answer is yes.

#4."“Is your position so weak it cannot withstand rational debate?” (“Data”, TNG). Looks like it, boys."

Bzzt . No, no it doesn't. You looked at the actual climatological data lately?

@5. Chris Kennedy : I wouldn't advise that personally tempting as it may be in some cases.

A much more pleasant alternative is trying enough alcoholhic beverages to raises ones blood alcohol level to, oh, say, a slight amount above the usual driving percentage limit. Still well under 1% but gee its a nice feeling if somewhat impairing of judgement and abilities and likely to lead to hang over t'next day and all .. Yeah, it doesn't take much and it won't kill you. Which a much, much smaller percentage of taking certain other poisons will do.

By Astrostevo (not verified) on 16 Jun 2015 #permalink

Using a 12 month moving average based on these data, we’ve had record or near record 12 month periods since some time in 2014.

Yes indeed.

2014 of course was the hottest year ever recorded just beating 2010 and 2005 a s this excellent article via NASA shows :


That the ten hottest years in human history have occurred since 1997?

Of course it flippin' isn't!

By Astrostevo (not verified) on 16 Jun 2015 #permalink

Astrostevo: I believe the 14, not just 10, hottest years ever recorded are all since 98 (inclusive of 98) - has several more links describing changes as well.

metzomagic, not a small point at all, a big error, but fixed, thanks!

Since the burning globe is obviously not intended to be taken literally, it is hyperbole in the literary sense and perfectly apt given the context.

John Carter,
Harris is a known quantity here. Like many deniers, he is willfully ignorant. How self-aware he is (exactly) may be unknowable, but at some level he knows he's full of it and is thinking that the ends justify the means. You can tell from how terse and slick he is in his use of sophistry. He is a professional propagandist. Read about him here:

By Obstreperous A… (not verified) on 16 Jun 2015 #permalink

@18. J Carter : Thanks. Yup. Uncoincidentally!

By Astrostevo (not verified) on 16 Jun 2015 #permalink


By Astrostevo (not verified) on 16 Jun 2015 #permalink

Tom Harris,
It is very easy to prove with 'data' that you're incorrect in a number of ways. People even went out of their way to do so when you were exposed as teaching anti-science to undergraduate students.

As a person studying climate-related topics in the Ottawa-area it is appalling to think that someone with as poor an understanding of the climate system as you was given a chance to teach at one of our fine local universities.

I have very little tolerance for those who mislead students. You should be ashamed - not only for misrepresenting the science but for failing to be a role model for those in your classes.

By Robert Way (not verified) on 16 Jun 2015 #permalink

"Good grief. The whole range of the above graphs is about 1 degree C." - Tom Harris

The increase from 1910 to 2015 is actually 1.3°C (and almost 1.4° in the second graph), a rise that is double the decrease from the mid-Holocene to the 18th century. To brush off that staggeringly rapid increase with a "good grief" reveals more about Mr. Harris' position than he might have cared to show.

Right-oh Magma. While Harris is no authority on climatology (despite his posturing), he certainly knows that this 1.3°C rise in such a short period is unprecedented and extremely worrying. But the majority of the public do not. A lot of these people still think the sun circles the earth and that during summer, the earth is closer to the sun and farther in winter. To them, a 1 degree increase in a century is nothing. These sheep are easy to shear for hucksters like Harris.

By Andrew Skolnick (not verified) on 17 Jun 2015 #permalink

In reply to by Magma (not verified)

To brush off that staggeringly rapid increase with a “good grief” reveals more about Mr. Harris’ position than he might have cared to show.

Harris' position was arrived at by his realizing that parroting the denialist line would be good for his bank account. It isn't obvious that he has any real position on the science, or whether he even understands any of it.

May turned out to be, in the NASA GISS data set, less warm than expected.

Even though this is so, May continues the statistically significant global warming trend in GISTEMP since October 1998 that became apparent in April.

When Skeptical Science gets around to incorporating the April and May figures in its calculator: , everyone will easily be able to see the statistically significant global warming in GISTEMP even with just data starting in 1998.

By Chris O'Neill (not verified) on 17 Jun 2015 #permalink

When Skeptical Science gets around to incorporating the April and May figures

Skeptical Science has now updated the figures, and incorporated the new NOAA data as well, but the new adjusted GISTEMP does not show statistically significant global warming from October 1998 to May 2015. Just have to wait another month or 2.

By Chris O'Neill (not verified) on 17 Jun 2015 #permalink

Tom Harris - if you're having trouble calulating the answers to the question I asked, maybe you could get some help from a more mathematically savvy faculty member at one of those fine Ottowa-area universities.
The conversion from ice mass loss to sea level rise can be derive from Velicogna who showed "The combined contribution of Greenland and Antarctica to global sea level rise is accelerating at a rate of 56 ± 17 Gt/yr2 during April 2002–February 2009, which corresponds to an equivalent acceleration in sea level rise of 0.17 ± 0.05 mm/yr2 during this time" and "The F-test show that the improvement obtained with the quadratic fit is statistical significant at a very high confidence level." doi:10.1029/2009GL040222
That was in 2009; a more accurate answer should include recent findings from - "We use satellite altimetry and gravity observations to show that a major portion of the region has, since 2009, destabilized. Ice mass loss of the marine-terminating glaciers has rapidly accelerated from close to balance in the 2000s to a sustained rate of –56 ± 8 gigatons per year, constituting a major fraction of Antarctica’s contribution to rising sea level. The widespread, simultaneous nature of the acceleration, in the absence of a persistent atmospheric forcing, points to an oceanic driving mechanism."

By Brian Dodge (not verified) on 19 Jun 2015 #permalink