Climate sensitivity low, alarmist sensitivity high

“[Connolley comment] Anyone saying “trust me, I’m an IPCC expert reviewer” is a cretin.”
But, doesn’t the IPCC keep saying, “trust us, we have 2500 expert reviewers”?

Nature isn’t co-operating. Gaia is a denaia!

I can hear the buttons loudly popping off the vestures that cloak the scientists of climate all the way to Central Java.
If anyone wanted to know what the end of climatism sounds like, this is it: a steamy stream of bile poured on those who point out that most inconvenient of truths, the jig is up.

Its dead simple, surface tension blocks heat. The atmosphere can’t heat the ocean.

pokerguy says:
December 20, 2012 at 7:57 am
..It’s not over by any means, but as it becomes ever more obvious that the IPCC has been exaggerating more and more scientists will be jumping ship to protect themselves. Once the rush for the exit starts in earnest, watch out below…
Totally agree – but those jumping ship will have a long swim – they have distanced themselves from the ‘ship of science’ by a long way as the vast majority of their many peer reviewed publictions will verify!! As I see it, they not only have to jump ship and swim like buggery to catch up, they will have to expunge their science ‘records’ too! Something I don’t think many will find it easy to do.

Hoping for the end of some careers of people who should never have been given any academic title at all.
But then again, that’s like hoping certain EU governments would reduce their spending once their nation is broke.

Well said, pokerguy. I wonder whether what will eventually kill this, is a growing realisation amongst scientists that are not climatologists, that CAGW has been overstated, and therefore that funding has been diverted from other scientific disciplines, arguably more worthy of the funding than climate science. This isn’t just a fraud against citizens, it impacts other government science too. I can imagine that many national science bodies could have huge swathes of their membership enraged at the climate fraud. I don’t know when this will happen, but I think most scientists must have realised by now that climatology is unusually controversial and unusually polarised. Surely this must get them curious to learn the facts? I believe that the overwhelming majority of scientifically literate people will realise that CAGW is overstated / a fraud if they take a few hours or maybe a day or two to examine the data. I think that when the end comes it will be an accelerating collapse. The reason I say this, is that it is hard for me to imagine that the perpertrators will be able to say “oh sorry, we made a mistake” and just walk away. Politicians are going to want someone to blame, and scientists will want to have got out before the politicians realise what is going on. Also, what happens when high profile scientists who today usually support CAGW want either to switch sides, or refuse to comment on CAGW claiming that its not their discipline. People will see scientists they trust either changing their views or being cagey and this will upset the masses, putting more pressure on the politicians. Some people and businesses have done very well out of this, and I think that the citizenry will expect that they face some sort of punishment.

You gotta love Matt Ridley’s tweet:
“Connolley must be a sceptic double agent, paid by Monckton and Big Koch surely? ”
The thread at Tim Worstall’s is a hoot. Connolley has succumbed completely to hysteria and definitively proven he should never again be taken seriously in matters concerning climate.

@Carter says:
December 20, 2012 at 8:21 am
FAO RMB
‘The atmosphere can’t heat the ocean’ so why is the Arctic ocean colder than most other oceans?
Because of the sun?

Kev-in-Uk says:
December 20, 2012 at 8:07 am
pokerguy says:
December 20, 2012 at 7:57 am
..It’s not over by any means, but as it becomes ever more obvious that the IPCC has been exaggerating more and more scientists will be jumping ship to protect themselves. Once the rush for the exit starts in earnest, watch out below…
Totally agree – but those jumping ship will have a long swim – they have distanced themselves from the ‘ship of science’ by a long way as the vast majority of their many peer reviewed publications will verify!! As I see it, they not only have to jump ship and swim like buggery to catch up, they will have to expunge their science ‘records’ too! Something I don’t think many will find it easy to do.
Not easy to do at all. The true believers will never admit they were wrong, whatever the evidence, or in this case the lack of, and will go to their deathbed arguing that it is all just around the corner still. Those not quite at the heart of the madness will delay as long as possible but will eventually heap blame on ‘other’ people who provided them with wrong information, undermining their own work in the process as well as loudly keening that they never said it was all catastrophic, they only said it MIGHT be and they have have changed their view in the light of the evidence which they had never said was incontrovertible or overwhelming (even if they did).
It is also well to remember that the majority of ‘climate science’ is of the type, given CAGW is certain what will be the effect on ….. etc.

Theo Goodwin – that’s made me chuckle!! 🙂

Must be the Mayan calendar is intended for the IPCC et. al.

FOA? Freaking All Over? Some one never escaped the language of bureaucratese.
Christmas comes early this year. The dam burst in 2009, the dirt has all eroded and now the flood begins to move.
Academia imitating nature?
Fooling lots of people once or twice is a sweet short term victory, unfortunately there is always fallout.
The politicians when put to the question will respond
.”I trusted my policy advisors from the bureaucracy” The bureaucrat, “I trusted the best scientists”
The scientists,”I,….I.. IEEEE.” The super computer tricked us?
Guess who gets thrown to the wolves first? And the wolves gather, poverty, destruction, distrust and decay bring them out.
Its our nature to have scapegoats for our group insanity and I am fully in support of my nature on this fraud.
Scams this vile and pernicious demand retribution.
Bad time to be wrapped in the trappings of climatology.

mpaul says:
”observed cooling effect is much lower than their modeled cooling effect.”
Let’s not forget that WHY they needed a large cooling effect from aerosols was to explain the lack of warming without including solar variation since they’ve repeated asserted only TSI matters and its variance is too small to account for the lack of warming.
It all goes back to only considering TSI variation of solar output in their models (both computer and mental).
News flash to climate scientists: The area under the curve of the solar output spectrum (TSI) is not the only variation in solar output that influences Earth’s climate. Variations in the position and shape of the curve (i.e.: more or less UV) matters as well.

Peter C,
Good points, Nor will the hardcore alarmist public likely ever admit to being wrong. You’d think they’d be happy things clearly look to be far from catastrophic. I swear to God, many of them woul drather we all fry just so they can say they were right…

Hey, here’s a happy thought. Desperation leads to desperate measures. Maybe one or two alarmists will even agree to a debate. Wouldn’t that be tasty….:-)

Has anyone read what Tamino says?
He says: “What should be done is to offset the observations so that the hotter-than-average 1990 really is hotter than average. When I offset the observations by 0.1 deg.C, we get more realistic comparison of observations to projections:”
then says: “It turns out that observed global temperature has gone “right down the middle” of the IPCC projections. But, fake skeptics want you to believe otherwise”
http://tamino.wordpress.com/2012/12/20/fake-skeptic-draws-fake-picture-of-global-temperature/#more-6082
I don’t quite follow his logic.

Mr. Ridley: “Only on climate (and religion) am I told that my credentials disallow me from even having a view.”
Doesn’t he realize they are now one and the same?

margaret berger says:
December 20, 2012 at 8:41 am
Those young earnest believers who are saving the planet will allow the parasites to milk this farce longer as they will be lost without a noble cause.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
The big problem/question is what is the next Cause De Jour in the pipeline. (Ocean Acidification?)
The professional astroturf establishment is not just going to go away, it will find another Chicken Little Scare to use to milk the masses. This has been going on since the first elder figured out he could use his knowledge/experience as a lever to extract tribute/wealth from the rest of the tribe and avoid being sacrificed when the food got scarce. Thus was the first shaman born.
This also goes for the scientists/universities who have been living high on the hog thanks to CAGW and all the little students with their hot new degrees in various green technofuzzy studies.
I can not find anything on the number of students graduating with green degrees such as ‘Sustainable Energy Management’, ‘Environmental Earth Science’, ‘Sustainable Energy’, ‘Windmill Technology’ ‘Environmental Management & Policy’ ‘Environmental Management’, Sustainable MBA Degree, and what ever else colleges and universities have dream up to entice students infected with the Bambi Syndrome and Climatitisis.
However as this news story shows those degrees are popular. All the students we used to see go into English, Biology, and history degree programs and even those in chemistry, physics or engineering are going to flock to the new green degrees with their high school counselors egging them on.

College students are flocking to sustainability degrees, careers
Students interested in pursuing a job in sustainability now can choose from a variety of “green” degree programs.
With an increased interest in the environment and growth in the “green collar” job sector, colleges and universities are beginning to incorporate sustainability into their programs. From MBAs in sustainable-business practices to programs that give students the technical training necessary to operate wind turbines, students have an increasing array of options to choose from….
A growing number of schools, including community colleges, are training students to operate green technology.

However just like those useless degree like ‘Women’s Studies’ are the graduates going to find jobs out there now or a few decades or more from now? Without tax payer support I would say no and with a financial cliff facing many countries what support there is will be going away soon.

Students pursue green degrees, but jobs lag
…The U.S. Bureau of Labor Statistics only recently started tracking the sector, figuring the nation had around 2.2 million green jobs. The bureau has not yet offered forecasts on expected growth from the sector….
The $25 billion set aside by the Obama administration two years ago has, so far, produced little in terms of job growth.
“It’s happening. But it’s happening at a very slow and methodical pace,”…. “Right now, the effect of the stimulus package is negligible.”

NASA 2008 Competitive Grant Programs
More U.S. college students studying clean energy
(Reuters) – Concern over global warming has more U.S. college students looking into careers in alternative energy, leading U.S. universities to add new courses on clean energy technologies and the environment.
“Students see an opportunity for challenging jobs and a way to do some good for the planet,” Dan Kammen, an energy professor at the University of California at Berkeley , said.
The number of Berkeley undergraduates enrolled in introductory energy courses has almost tripled and a new graduate class in solar photovoltaics signed up 70 students, the largest course in recent memory at UC’s College of Engineering .
“Over the last two years, demand for energy courses is off the charts here,” Kammen said….

Connolley with an (e) the climate science luddites,luddite…still missing the gravy train no doubt LOL
Never mind Wil wait long enough and another scare will be along soon, this time remember to be at the right station and to get on the train earlier LOL LOL LOL!

jorgekafkazar says: December 20, 2012 at 8:57 am
” RMB says: “Its dead simple, surface tension blocks heat. The atmosphere can’t heat the ocean.”
Do you have any proof of this premise, other than your frequent assertions? Calculations? References? Experiments? Anything? ”
@jorge
Try heating the water in your bathtub by turning on the heater in your bathroom. Keep me posted!

“Phyllograptus says:
December 20, 2012 at 7:40 am
There is evidence based decision making & decision based evidence making. Guess which none the IPCC has been using”
Very Clever and to the point!

James at 48 says:
December 20, 2012 at 12:08 pm
The house of cards is falling down. Now let us hope that awareness of the very real threat posed by killer cold can be addressed. The current interglacial is a gift and the current warm period within it is icing on the cake…..
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Unfortunately the very real threat posed by killer cold is treated openly as a ‘conspiracy theory’ even here on WUWT.
Is the Climate going to cool? Eventually since we are towards the end of this interglacial. Are we going to see cooling in the next few decades? I think so but there are plenty of people who would call me nuts. Unfortunately while warming and an increase of CO2 are not a threat cooling is and because the Climastrologists have been dicking with the temperature record we really have no idea whether or not it is actually cooling. Dr Spencer’s data is the closest we come to un-mucked up data.
For what it is worth this is what I am watching
graph
graph
What frightens the dickens out of me is the way the Ag Cartel ably aided by politicians is messing with the food supply but that is 11 pages just to hit the highlights. (The USA grows ~ 25% of the world’s grain and no longer has strategic grain reserves and my state just made it illegal for me to give neighbors my homegrown veggies.)

Water is opaque to infrared i.e., greenhouse gas radiation. See the absorbency spectrum of water. SST is totally unaffected by the greenhouse effect. Sea surface temperature is determined by insolation in the short wave spectrum i.e., visible light. This is one of the earth-sized holes in AGW theory.
—
Half right.
Water temperature is determined by energy in vs energy out. Solar insulation counts for most of the energy in, however the temperature of the atmosphere directly affects the rate at which energy can leave the oceans. So a warmer atmosphere will result in a warmer ocean, because less energy is escaping rather than more energy entering.

Opps 16 years.

It’s not over by any means, but as it becomes ever more obvious that the IPCC has been exaggerating more and more scientists will be jumping ship to protect themselves. Once the rush for the exit starts in earnest, watch out below.
—-
The problem is that there are a number of prestigious “scientists” and “scientific organizations” that have bet there entire career on pushing this scam. They can’t back out now without completely losing their credibility and quite possibly, jobs. These people and groups will continue to fight a rear guard action for as long as they can. They have to milk enough out of thise before it collapses to ensure they can live comfortably in retirement.

Carter, @ where he comes unglued above.
==============================================
Golly, how excitable you are. What you see on my comment is a standard convention. All below the hatched line is my response to your comment at the time given above it.
Please pardon my attempt to enlighten you.It won’t happen again, I promise.

Gail Combs says:
December 20, 2012 at 11:28 am
“The professional astroturf establishment is not just going to go away, it will find another Chicken Little Scare to use to milk the masses.”
Steven Crowder tries a job at CALPIRG:

MarkW says:
December 20, 2012 at 12:38 pm
A warmer atmosphere may or may not be able to warm the oceans, however a warmer atmosphere does make it harder for the oceans to transfer the heat the sun is putting into it up to the atmosphere.
So in the end, the result is the same.

and
MarkW says:
December 20, 2012 at 12:43 pm
Water is opaque to infrared i.e., greenhouse gas radiation. See the absorbency spectrum of water. SST is totally unaffected by the greenhouse effect. Sea surface temperature is determined by insolation in the short wave spectrum i.e., visible light. This is one of the earth-sized holes in AGW theory.
—
Half right.
Water temperature is determined by energy in vs energy out. Solar insulation counts for most of the energy in, however the temperature of the atmosphere directly affects the rate at which energy can leave the oceans. So a warmer atmosphere will result in a warmer ocean, because less energy is escaping rather than more energy entering.

1. A warmer atmosphere makes it easier for water to evaporate as warmer air can hold more water vapor. Therefore, warmer air is likely to cool the water surface as water evaporates from it. The amount of cooling can be significant as the latent heat of evaporation is 540 calories/gram (i,e, 540 grams of water reduced in temperature by 1C).
2. Humid air is lighter than dry air at the same temperature so will rise convectively and draw in more dry air underneath where the process will repeat – cooling the water and humidifying the air but not warming it as the water vapor is carrying latent heat..
3. The rising water vapor will eventually form clouds and give up the latent heat of condensation. The clouds will raise the albedo and reduce the short wave radiation from the sun that penetrates the photic layer reducing the heating effect of the sun.
4. Water is opaque to infrared so the first few molecules of the surface will be excited by the infrared and this will assist them to evaporate taking some more heat from the surface. It will not heat the body of water below the first few molecules – it will cool it. The small amount of infrared that is purported to be downwelling due to CO2 scattering, is unlikely to have any measurable effect.
From the above you will see that a warmer atmosphere will result in a cooler ocean as more water evaporates taking the latent heat from the surface. This is how hurricanes form after all and they are getting all their energy from the sea below despite the winds being very warm. Only the short wave radiation from the Sun will heat the water and in the tropics with the Sun overhead the photic layer is deep and the oceans warm rapidly during the day. However at the poles are the ocean surface layers are cold as they can lose heat readily into the dry cold air above but there is very little solar heating due to the insolation of what sun there is being at an angle at which water is effectively reflective.

Gail Combs says:
December 20, 2012 at 11:28 am
Excellent post. I understand your concern with “the next big scare.” However, worthless studies tied to causes are highly fungible within the academic empire. Biology Departments have all kinds of specialties that are soft science at best but that have been growing steadily since Earth Day 1970. I know a college that has an “at large” Professor of Green, as if he were teaching a lifestyle or something. I believe he is employed through the office of Diversity Dean.
I doubt that what I have said is a surprise. After all, most of the people associated with the CAGW narrative are not what we once called “hard scientists.”

MarkW says: December 20, 2012 at 12:43 pm
Half right.
Water temperature is determined by energy in vs energy out. Solar insulation counts for most of the energy in, however the temperature of the atmosphere directly affects the rate at which energy can leave the oceans. So a warmer atmosphere will result in a warmer ocean, because less energy is escaping rather than more energy entering.
========================================
Yes, just as I gave, insolation determines SST, which determines atmospheric temperature, not the other way around. The greenhouse effect on SST is inconsequential. See Bob Tisdales posts on WUWT that very thoroughly address this topic.

Yes, warmer air would result in a lower RH which would result in increased evaporation, but only til the RH returned to equilibrium. Once that point is reached there is no enhanced evaporation and we reach the point where the only difference is less energy leaving the ocean via conduction to the air.

MarkW says: December 20, 2012 at 2:19 pm
Yes, warmer air would result in a lower RH which would result in increased evaporation, but only til the RH returned to equilibrium. Once that point is reached there is no enhanced evaporation and we reach the point where the only difference is less energy leaving the ocean via conduction to the air.
==============================
The warmer the SST, the warmer the air. RH returns to equilibrium only at RC.

Theo Goodwin says:
December 20, 2012 at 1:46 pm
Gail Combs says:
December 20, 2012 at 11:28 am
Excellent post. I understand your concern with “the next big scare.” However, worthless studies tied to causes are highly fungible within the academic empire. Biology Departments have all kinds of specialties that are soft science at best but that have been growing steadily since Earth Day 1970….
>>>>>>>>>>>>>>>>>>>>>>
Tell me about it. I was a chemistry major and as a senior topics course in 1971 in chemistry (like a masters paper only assigned) I got stuck with research in ‘Chemical Oxygen demand in polluted waters’ In other words I was the lab tech grunt for my profs next paper.

latent heat of evaporation is 540 calories/gram (i,e, 540 grams of water reduced in temperature by 1C

540 calories (2260 joules) is absorbed (released) by 1 gram of water evaporating (condensing).
the specific heat of water is 4.2 joules/gram which is the energy required to raise its temperature by 1 degree C.
both of these numbers vary slightly with temperature and pressure.

Roger Knights says:
December 20, 2012 at 2:51 pm
“My fingers can now type the first tag without conscious thought. ”
Download Firefox, the Greasemonkey plugin and the CA assistant from Climate Audit. It gives you formatting buttons in the edit box.

The whole CAGW crowd must be feeling pretty sick with fear at the moment. They are definitely between a rock and a hard place. The most honourable of them – and big apologies to those who just spluttered coffee at my use of the term – will confess all. It will hurt, and hurt quite a bit, but they will then feel a lot better for coming clean. It really is their only way out of the mess they’ve made. All their conniving has only ever gotten them deeper into trouble, so conniving some more will not help them any. Basically they should come out with their hands up or suffer the consequences. I won’t hold my breath on their surrender. After all, that takes courage.
Here in Australia, it is the 21st Dec today. The end of the world? Oh yes, for some, by the looks of it, but then, that’s what the CAGW community wanted, right? Maybe it’s just for them. Maybe they should have been careful what they wished for.

george e. smith,
Correctomundo. And the proposed tax increase will go for more spending, as if the Administration is not already spending like drunken sailors. There will be a few token cuts, but they will be smoke and mirrors. By the end of Obama’s second term, I expect a deficit of around $25 Trillion. And they will have their hand out for more tax increases.

“I can make a firm pledge. Under my plan, no family making less than $250,000 a year will see any form of tax increase. Not your income tax, not your payroll tax, not your capital gains taxes, not any of your taxes.”

–Candidate Barack Obama, Sept. 12, 2008
“If your family earns less than $250,000 a year, you will not see your taxes increased a single dime. I repeat: not one single dime.”

–President Barack Obama, Feb. 24, 2009
“The statement didn’t come with caveats.”
–Obama spokesman Robert Gibbs, April 15, 2009, when asked if the pledge applies to healthcare 

They lie through their teeth.

Baa Humbug says:
December 20, 2012 at 8:48 am
The GHE hypothesis says the atmosphere isn’t heated by direct insolation (shortwave), only upwelling longwave from the surface heats the atmosphere which in turn heats the surface some more.
The GHE hypothesis doesn’t say that the atmosphere isn’t heated by direct insolation – water vapour absorbs a good proportion of shortwave IR, ozone absorbs UV. You’ve also omitted conduction/convection. Even Wikipedia gets that right.

One must be careful with evaporation of sea water. It is not driven just by temperature, but also by the current humidity of the air above the water, relative to its temperature. Is more to do with diffusion or solubility, and moisture holding capacity of the adjacent air.
If the air immediately above the water is already holding 100% of its vapour capacity at its particular temperature, then evaporation is very difficult.

mpainter says:
December 20, 2012 at 3:49 pm
You couldn’t be more wrong, Phillip. The arctic is cold because of lack of insolation. Kindergarten stuff. Air does not determine SST. That is backwards.
Were the oceans static, you’d have a point, but they are not. Water currently in the Arctic Ocean was at some point in the Tropics. As that water moved from the Tropics to the Arctic it got colder because the air above it got colder.
I guess ice forming on water surfaces when the air temperature drops below zero is just my imagination at work. 😉

joelshore cherry-picks 1975. Well, two can play that game.

Although global warming has stopped, and is now headed down, it may resume at some point. Therefore, the only legitimate way to look at it is on the longest time frame for which we have reasonably accurate records.
This shows that the long term global warming trend has remained within well defined parameters. Global warming has not accelerated, despite the rise in CO2. Therefore, CO2 has had no measurable effect. In fact, the green trend line shows that the warming trend has been slowing.
Since CO2 has had no measurable effect on global warming, and since global warming has not accelerated — but rather, has stopped for the past decade and a half — the only scientifically rational conclusion is that AGW remains a failed conjecture. AGW may exist, but if so, it is merely a minor third order forcing — far too minuscule to affect global temperatures in any meaningful way.
The short term coincidental correlation between rising CO2 and rising global temperatures is broken. CO2 continues to rise, but temperatures are no longer rising. Any honest scientist would completely reconsider the CO2=AGW conjecture at this point. But as we have repeatedly seen, when the alarmist clique is faced with a contradictory choice between what their models say, and what the planet is saying, they typically discard the empirical evidence and argue instead that their always-inaccurate computer models are reality. Such mendacious pseudo-science is the reason the climate alarmist crowd has lost all credibility among honest scientists.

joelshore,
Not really.
I have robustly demonstrated that there is no empirical, testable evidence showing that CO2 makes any measurable difference. All the real world evidence shows that CO2 is benign and beneficial. More is better. There is no verifiable scientific evidence of global harm from the rise in CO2. Therefore, CO2 is harmless, based on the complete lack of evidence to the contrary.
You always avoid that fact. If CO2 had the claimed effect, global temperatures would be rising smartly. They are not. Global temperatures are not currently rising at all. Thus, AGW is only an extremely minor, third order forcing that can be completely disregarded for all practical purposes. That is what Planet Earth is clearly demonstrating.
Finally, you are making an arbitrary distinction between the number of years you wish to cherry-pick. The IPCC admits that they now have a serious problem. But you keep digging your hole deeper. Wise up. Look out your window. There is nothing unprecedented happening. Nothing. Learn anbout the Null Hypothesis. This has all happened before, and to a much greater degree — and when CO2 was much lower.

joeldshore says:
December 23, 2012 at 3:10 pm
So, no, we are not playing the same game
O.K. I will play your game. From what you have written, I will assume that 20 years and 28 years are long enough to draw appropriate conclusions.
What I assumed was that warming did not stop in 1997, but rather that the temperatures follow a (very poor) sine wave. So if there was a slope of 0 for 16 years, then the top of the sine wave would be after 8 years or at 2005. You could argue that a flat slope of 16 years consists of warming for 8 years and then identical cooling for 8 years. If you get the slope from 1985 to 2005 and then from 1985 to date, the latter slope is lower as shown below. See:
http://www.woodfortrees.org/plot/hadcrut3gl/from:1985/plot/hadcrut3gl/from:1985/trend/plot/hadcrut3gl/from:1985/to:2005/trend/plot/hadcrut3gl/from:1997/to:2005/trend/plot/hadcrut3gl/from:2005/trend

Werner Brozek says:

You could argue that a flat slope of 16 years consists of warming for 8 years and then identical cooling for 8 years. If you get the slope from 1985 to 2005 and then from 1985 to date, the latter slope is lower as shown below.

You are fitting to noise. Why don’t you try computing the uncertainties on those trendlines of yours.
Have a good holiday everyone!

RMB says:
December 20, 2012 at 7:59 am
Its dead simple, surface tension blocks heat. The atmosphere can’t heat the ocean.

Take a plastic wrapping film, as tough as you like, and hold it up to your face, as taut as you like. Then I’m going to punch the film. Hard, and often. With my handy-dandy brass knucks.
How long do you think you can keep your face from getting “warm”?

joeldshore says:
December 23, 2012 at 5:05 pm
Why don’t you try computing the uncertainties on those trendlines of yours.
I agree that the slopes in both cases give significant warming, but I was replying to a different point of yours earlier:
As you can see, a fit of the HADCRUT4 data from 1975 to mid 1997 actually gives a slightly lower slope than a fit of the data from 1975 to the present
The “slightly lower” slope to 1997 may give some people the impression that global warming is accelerating. My choice of lines shows at least a slowing down of the warming.