Are You New To the Global Warming Debate? James Hansen Admits a Couple of Things about Global Temperatures and Sea Levels You Should Know

Guest Post by Bob Tisdale

Yale University’s Katherine Bagley interviewed James Hansen, former director of NASA’s Goddard Institute for Space Studies, in the post For James Hansen, the Science Demands Activism on Climate at YaleEnvironment360.  That interview was replayed in the article Climate scientist James Hansen ‘I don’t think I’m an alarmist’ at The Guardian.

In that interview, Hansen admitted a couple of basic things that many people do not realize.  So if you’re new to discussions of global warming and rising sea levels read on.

First, global surface temperatures were warmer during the last interglacial than they are today.  An interglacial is a period between ice ages.  That will be news to many readers.

How then, many will wonder, do we know for sure that the recent warming was caused by manmade greenhouse gases since we’re still within the realm of natural variability?

Of course the answer is: Climate models tell us so, even though those climate models are not simulating Earth’s climate as it existed in the past, as it exists now, and as it might exist in the future…climate models do not simulate naturally occurring ocean-atmosphere processes that can cause global warming.

Hansen’s second admission was sea levels were 6 to 9 meters (20 to 30 feet) higher during the last interglacial than they are today.  Here’s an illustration from my ebook On Global Warming and the Illusion of Control – Part 1 (700+ page, 25MB .pdf).

Figure Intro-17

But what Hansen failed to say is that paleoclimatological studies have indicated that it took a number of millennia for sea levels to rise those 6 to 9 meters when temperatures were warmer than today. See:

The corresponding portion of the Hansen interview (my boldface and brackets):

James Hansen: We know from the earth’s history that 2 degrees would eventually lead to sea level rise of several meters. The last inner glacial [sic] period,  [that should read interglacial period] 120,000 years ago, that’s the last time it was warmer than today, sea level was 6 to 9 meters higher — that would mean loss of almost all coastal cities. It’s unthinkable that we walk into such a situation with our eyes open, and yet, the science is very well understood.

There’s no argument about the fact that we will lose the coastal areas, now occupied by most of the large cities of the world. It’s only a question of how soon. That message, I don’t think, has been clearly brought to the policymakers and the public…

If I was new to the discussions of global warming and sea level rise, that would be as far as I would have needed to read the interview.  He would have turned me into a skeptic right there.

But contrary to his claims about alarmism, Hansen then goes on to play alarmist and discuss how his recent modeling efforts and resulting paper indicate that the rise maybe-sorta-could occur abruptly.

… More than 190 nations agreed [at the Paris climate conference last December] that we should avoid dangerous human-made climate change. That loss of coastal cities would be a dangerous outcome. It’s hard to imagine that the world will be governable if this happened relatively rapidly. What we conclude is that the timescale for ice-sheet disintegration is probably a lot shorter than has been assumed in the intergovernmental discussions.

Of course, even proponents of the hypothesis of human-induced global warming found the recent Hansen et al. (2016) study (Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming could be dangerous) to be nonsense. Even the title of the paper includes the oft-used weasel words “could be”.  See the following posts at WattsUpWithThat:


Two quotes from my ebook On Global Warming and the Illusion of Control – Part 1.

From the Closing to Chapter 1.16 – Sea Levels Are Rising:

This chapter opened: For many people, especially for persons living near the coasts, sea level is the critical metric associated with global warming and climate change.

Sea levels have risen since the peak of the last ice age, and, if history repeats itself, they will continue to rise to the heights achieved during the last interglacial: 5 to 10 meters (16 to 32 feet) higher.

But as discussed in this chapter, there are a multitude of factors that can contribute to the rise, or fall, in local sea level. Rising sea levels are, therefore, a local concern, as are steps to combat it, as I’ve noted numerous times in this chapter. Many countries and communities are already implementing measures to reduce the impacts of rising sea levels—employing methods designed specifically for their location.

Assuming that man-made greenhouse gases have contributed to the rate at which global sea levels are rising, curtailing man-made greenhouse gas emissions would only slow the rate, not stop it. Then again, The Houston & Dean (2010) Sea-Level Acceleration Based on U.S. Tide Gauges and Extensions of Previous Global-Gauge Analyses found that the rise in sea levels had not accelerated with global warming.

And from the Introduction, I began the discussion under the heading of SEA LEVELS, ON THE OTHER HAND, PRESENT AN ENTIRELY DIFFERENT PROBLEM:

Again, even if we could turn back CO2 levels to preindustrial values, sea levels would continue to rise. Sea levels have been rising since the end of the last ice age, and they will continue to do so until Earth cools once again and we head toward another ice age. That is, the only way to stop sea levels from rising is to start accumulating water on land in the form of ice.

Further, the rate at which global sea levels might possibly change in the future, in response to the hypothetical effects of man-made greenhouse gases, is still the subject of wide ranges of uncertainty and open debate…and the subject of even more alarmism from activists and the media, if that’s possible.

And I closed the discussion under that heading with:

The ridiculous suggestions by politicians and alarmists that we can control rising sea levels by reducing greenhouse gas emissions is one of the primary reasons for the title of this book: On Global Warming and the Illusion of Control.

UPDATE:  I corrected a typo in the opening sentence.


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Based on what we know about all Interglacials is…they are all very, very short, they all begin very, very suddenly and they all end falling off a cliff straight into the coldest part of every Ice Age.
Knowing these painfully obvious facts, pretending we are getting warmer and warmer when we are no where near as warm as when this present Interglacial began, it baffles me about how worried these warm alarmists are. If they are truly so scared, why are they moving as close to the oceans as possible and moving to warm parts of the planet, not Burrow, Alaska.


..It has never been about the climate of the Earth, it is about power and control of the Earth !


I would have said it’s about control of others. I don’t think that even these megalomaniacs believe that they can control the earth.


Actually both you and Mark are right. The megalomaniacs don’t necessarily believe they can control the earth(though they might). But the folks they wish to control, those are the ones gullible enough to believe that by giving the control freaks power they can do just that!

Crispin in Waterloo

Real control of people through pretend control of the climate. Sums it up.


And the interglacials end when CO2 is at its highest levels during the interglacial. Doesn’t say much for CO2’s warming ability.


And Ice Ages always end when CO2 is lowest. This is worth repeating. Ice Ages always start when CO2 is highest and end when CO2 is lowest. So, based on the evidence, the idea that rising CO2 is most likely to lead to runaway warming is pure poppycock. It never has in the past. What rising CO2 leads to is another Ice Age.

I find it amazing that on a climate science blog people are seemingly ignorant of the reason Earth has IA’s/Inter-glacials.
I would suggest that you Google “Milankovitch cycles” …..
Inter-glacials end because of a slow descent into less TSI falling on NH land mass as Earth’s orbital characteristics change.
CO2 cannot stop an IA when it is in balance between sinks/sources. CO2 is then a feedback and it’s fall contributes to the descent to colder global temps.
It is only a driver if it’s concentration rises artificially (Vis volcanic eruption or Anthro).
Answers on the back of a post-card as to the current culprit.

Horace Jason Oxboggle

But man-made CO2 is not the same as natural CO2, and thus produces different outcomes! Jimmy knows, but we ignorami don’t!

John M. Ware

They would fail completely in moving to Burrow, AK, since (I believe) there is no such place. There is Barrow, AK, which has cool summers and cold winters. Perhaps they could go sunbathing next to the Arctic Ocean. Brrrr.


emsnews – think you mean Barrow, not Burrow 🙂 BTW, Fairbanks, a much more people and cost effective location, gets much colder (and warmer) and does not have to deal with complete darkness several months each year.

Thanks Bob

Claude Harvey

Who knew? “Yale University’s Katherine Bagley interviewed James Hansen, former director of NASA’s Goddard Institute for Spade Studies.”


HAHAHA. Dig deep, dig hard.


.Awesome, thanks Bob !!

So we should do something totally useless and very expensive. Is Hansen channeling Pharoah Cheops’ architect?

Bruce Cobb

James “coal-trains-of death” Hansen claims he’s “not an alarmist”, because people are stupid. Okey-dokey Jim-Jims. If you say so.


He is merely the little boy who cried wolf. ‘We are all going to roast to death’ as glaciers grow.

Janice Moore

… and no one is listening to him anymore. Ha … ha … HA!


No, Hansen isn’t an alarmist. Saying that continued use of fossil fuels will mean that “the Venus syndrome is a dead certainty” isn’t alarming in the slightest. There’s something relaxing about watching the oceans boil and evaporate away. /Sarc

Janice Moore

Q: How then, many will wonder, do we know for sure that the recent warming was caused by manmade greenhouse gases …
Given that this article is aimed at those “new to the debate,” I would suggest more simple, direct, powerful, language should be used, for example, this phrase could easily mislead a new learner:
A: Of course the answer is: Climate models tell us so, even though those climate models are not simulating Earth’s climate …
While you add the qualification, “even though those models are not simulating…,” the statement could be better stated:
The answer is: we do not know this. There is not one piece of observational evidence that establishes a causation mechanism between human CO2 (or any CO2, for that matter) and enduring, planet-wide, climate change. Not one. There is only conjecture. Even those who “believe” human CO2 causes some small warming have only their belief, yes, based on theoretical laboratory physics, but never once proven in the real world.
The climate models touted by the warmists cannot hindcast historical temperatures and their future projections of temperature are SO far off the mark that they can be said to be: UNFIT FOR PURPOSE.
{See my book: Climate Models Fail: (insert link) 🙂 }
That said, BOB, THIS IS A VERY GOOD ARTICLE — just not written to promote understanding in one unfamiliar with the AGW arguments.
Thank you for sharing more of your excellent scientific analysis,

Emergent structures analysis demonstrates CO2 has no significant effect on average global temperature.


Unless I am mistaken (and please correct me if I’m wrong), there is no analytical way to determine man made CO2 from any other CO2 from an air sample.

The ‘best’ Kopp estimate is an Eemian sea level high stand 6.6-7 meters above present, which took about 3 millennia (30 centuries) to accomplish. The IPCC estimate for global Eemian is +2C above present, although NEEM shows north central Greenland was +8C. That is an average SLR of 23cm/century. The long record reasonably geostationary tide gauge estimate is a present 18-20 cm/century. Maks sense that warmer Eemian woild have experienced somewhat higher SLR.
There is no evidence except in Hansen’s overwrought models for a more sudden WAIS ice aheet collapse as Hansen intimates in the interview. The two papers claiming to find it during the Eemian disagree about the amount (by 2 meters) and the timing (by 3 millennia). Both papers are flawed as there is a simple common explanation. One of the two (OLeary in Nature Geoscience) comprises clearcut academic misconduct. Essay By Land or by Sea provides details.

Steve M. From TN

IIRC, sea levels during this interglacial have been 3-6 feet higher then they are now…
“The characteristic change observed at continental sites far from the ice sheet is a rapid rise in sea-level up to about 6000 years ago, culminating in a highstand of 1-2 m above the present level,” (Late Pleistocene, Holocene and present sea-levels:constraints on future change, Lambeck 1990)


Yes, we’re about 8000 years past the interglacial optimum. Sea level was higher in the Eemian but that was during the optimum then, too. Hansen’s left that little peice of information out of his fear-mongering.


Tisdale, are you going to release your book in an ebook reader format?

Gary Kerkin

It is easy to accomplish in iOS. Open the link to the book in Safari, touch the page and then “Open in iBooks”. I haven’t explored doing it on a Mac, but I would think it is just as easy. Don’t know about Windows or Android.


Hansen says “we should avoid dangerous human-made climate change”.
I’m sure everyone would agree with that – more even than the mythical 97%, I’m sure.
Fortunately, the evidence that dangerous human-made climate change might actually happen is almost non-existent, so no worries.

The Original Mike M

Only the dangerous kind though. If warmer and more CO2 are better for the planet then we should be congratulating ourselves IF we are somehow responsible.

Waiting on the West Side Highway

I have a question for the educated readers of this website.
Some years ago Thor Heyerdahl was working in India. He found an ancient port (about 6000 years old) in India, which was roughly 150 feet above today’s mean sea level. Anyone remember this? He apparently got interested in this because of cowrie shells (an ancient medium of exchange, grown principally offshore in the Maldives). Cowries have been found in Greenland! Heyerdahl’s thesis was that sea travel was much more common several thousand years ago than has been realized. This was an offshoot of his theory that the Polynesians made it all the way to Mexico. A LONG time ago.

John F. Hultquist

No, but underwater works:
Marine scientists say archaeological remains discovered 36 metres (120 feet) underwater in the Gulf of Cambay …
older than Harappan


Couteau once spoke about a small deep beach he explored at about -120 meters where he could observe a big heap of opened oysters as if they had been gathered and eaten by prehistoric men.


Sorry: CouSteau, not “Couteau’.

the Polynesians made it all the way to Mexico. A LONG time ago.
Having learned how to sail eastward against the prevailing Trades, which is how they settled the tropical Pacific, it seems likely they would have made it to the Americas.


I don’t remember which animal it was, might have been the pig.
South American varieties are genetically very similar to their Polynesian cousins, and archeological evidence shows that they have been present well prior to the Alaskan ice passage forming.

Tom Yoke

I am by no means an expert on this question, but I do know that India is riding one of the fastest moving tectonic plates. Among other implications, one result of that is that the Himalayas are still getting taller.
Here is a GIF which illustrates the dramatic motion of India heading north through the Indian ocean


Excuse me if I may,… Find the DVD KonTiki or the book and you will discover that Thor proved by example that it was possible for the people of “South America” (along the western coast) were the ones who settled the Polynesian Islands. I recall reading the book as a child and recently watched a modern dramatization of his building of the Balsa log raft along with his crew. His conviction was extraordinary considering the fact that he couldn’t swim. Suffice it to say that his accomplishment flew in the face of the days “expert anthropologists”. In other words he pissed them off!
Actually, as many on this site well know, that is an easy thing to do especially in science that has been politicized.


There’s a lot of tectonics going on in India as it continues its push into [literally] Asia.
As a consequence southern Tibet is rising at about 16mm/year.
If Heyerdahl was correct about the age of the port [he was better as an adventurer than as a diligent archeologist] and we grant it the uplift rate of southern Tibet over 6000 years it could have risen 96 metres.
That’s about twice the height above sea level suggested by Heyerdahl.
The port is unlikely to have been rising at that average rate and local tectonic conditions would likely have had more influence than the average uplift rate but a rise of 150 feet over 6000 years is not out of the question.

Clyde Spencer

“…Goddard Institute for Spade Studies?” Is that “Calling a spade a spade?”


I think it is taking a dig at


I think it is taking a dig at NASA’s climatologists, I was trying to say.
I will get the hang of these keyboard thingies one day …


No need, none of the rest of us have bothe

David in Texas

My usual rant:
> An interglacial is a period between ice ages.
Correction: An interglacial is period between glacial periods.
We are currently living in the Pleistocene ice age which began about 2.6 million years ago.
Yes, glacial periods are referred to colloquially as ice ages (see Disney films), but this confuses the issue. We are currently living in exceptionally cold geological times. Over the last 500 to 600 million years the earth has been typically some 10°C warmer than the present.


..The Weather Network considers humans an ” Invasive ” species on planet Earth ! ( but they still can’t get the forecast right beyond 12 hours )


An invasive species is defined as any species that is found outside the area where it evolved.
Since humans are thought to have evolved in Africa, that would make us an invasive species anywhere outside of Africa.
On the other hand, species that have migrated on their own from one area to another, are not normally considered invasive. Which would make us humans non-invasive since we done it on our own. (Unless Von Daniken is right.)

Von Daniken is clearly way LEFT.

Eugene WR Gallun

Here in Oregon Hansen has organized a group of 21 children who are suing the federal government over climate change. The children’s claim is that it is destroying their future.
The children would do better to sue about the national debt. A former NASA employee, Hansen’s junk science has influenced federal policy and added immeasurably to that debt. Maybe the kids should sue him.
More holy than thou
He warns you of Venus
The only thing now
That hardens his penis
He rants at the crowds
A coot with the hypers
His mind in the clouds
A load in his diapers
He quotes from the Greens —
We work for the many!
(But really that means
They’re after the money.)
He quotes from the Reds —
Consensus is dictum!
(Good Socialist heads
Are all up one rectum!)
A fascist he cries
This Goebbels of weather —
The truth is in lies
The bigger the better!
So just like a skunk
His sight is alarming
His science is junk
There’s no global warming
Eugene WR Gallun

Owen in GA

Bob, I know you probably didn’t mean it but is Hansen really “former director of NASA’s Goddard Institute for Spade Studies”? Now we know why their reports are so messed up – they keep hitting the equipment with a shovel.

Eugene WR Gallun

The Goddard Institute for Spade Studies
Here comes Black Lies Matter!
Eugene WR Gallun


What if Mother Earth doesn’t warm any more for another hundred years (or two)? Let’s say that it stays about where it is, +/- 0.5C . . just oscillates/wobbles back and forth.
Seeing as how this is warmer than the era of the LIA, and that generally speaking, glaciers continue to melt (in starts and stops) globally, would not this continue at more or less the same rate well into that future, even without any additional warming?
So – even if they get to a point where they think that they’ve stopped some future 1-2C rise in global temperatures, what’s the actual result to be? More of the same, I suspect.
Obama was right (LOL) ‘we’ve got to stop the rise of the seas. .’ not just stop GW . . err, AGW.


Human population is growing and the average energy use of each human is increasing. Wouldn’t it be ironic if those factors result in terrible damage to the future habitability on earth having nothing to do with CO2. Is it possible we are focused on CO2 while the earth is approaching some unrelated crisis?
Predictions of disaster from overpopulation have so far proven wrong. The environmentalists have done a good job in dealing with air and surface water pollution. But lately they have narrowly focused on CO2
The four horsemen are still lurking out there somewhere.


Too many humans would only be a problem if we were to start running out of some vital resource.
We are nowhere close to running short of any resource.

Steve Fraser

Common sense?


–That is, the only way to stop sea levels from rising is to start accumulating water on land in the form of ice. —
That would be the quickest way- could happen within a century or two. Another way is to cool the average temperature of the Ocean [not just the surface temperature but whole ocean].
It’s possible to mix the surface waters with most of ocean being cold and thereby rapidly cool the surface, but cooling the entire ocean would take a lot to time.
Or both warming or cooling the entire ocean is something which should require thousands of years [or not a couple centuries- unless hit by giant space rock or massive volcanic activity {or nearby supernova or whatever].
So if the average temperature of the entire ocean were to lower by 1 C, one would lower sea level, as one would cause sea level rise if warmed the entire ocean {how last interglacial period, Eemian had higher sea levels and why over last few thousands years we have had rising sea level and why in next few thousands years we will continue to have rising sea levels- unless we enter a period like the Little Ice Age, but instead of ending after several centuries as LIA did, it continues for thousands of years and become even cooler [we enter the next Glacial period {which we don’t know when it will start, but can be fairly certain it will begin within next 5000 to 10000 years- or at least so it has in the past. If we had actual climate science rather than the pseudo science we have- we might get a clue of when next glacial period might start- which would be important- and fantasies of Earth boiling, are just delusional fanstasies].

Sandy In Limousin

When first confronted by the man made climate change scare many years ago I fell back on first principles and you ask yourself several questions:
1 Has Earth been warmer than it is now?
2. Has Earth been colder than it is now?
3. Has Earth had a drier atmosphere than it has now?
4. Has Earth had a wetter/more humid atmosphere than it has now?
5. Has Earth had Higher sea-levels than now?
6. Has Earth had lower sea-levels than now?
7 Has Earth had more ice-snow cover than now?
8 Has Earth had less ice-snow cover than now?
That is the basic list, although there are more questions you can ask. If the answer to any of the that list is a definite “No” then you could become a little concerned, if the answer to half is “No” then you could be greatly concerned. However as the answer to all is “Yes, and by quite a margin” then you have to wonder what all the fuss is about. Coupled with the question (for the UK)
What do you do for power when the wind isn’t blowing and the sun isn’t shining and it’s slack water?
No AGW fanatic has come up with an answer that has even come near to convincing me that Climate Change is one of the greatest threats mankind is facing or that renewables are a solution

Mickey Reno

The man who says coal trains are death trains IS an alarmist. No other data points are required.


“120,000 years ago, that’s the last time it was warmer than today”
BULLS**T !!!
The whole first 3/4 or more of the current interglacial were warmer than current temperatures.