Interview with Professor William Gray* by Terry Ally
Wednesday, April 11, 2001
Washington DC
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*Gray is a Professor of Atmospheric Science at
Colorado State University
and perhaps is the world's best known hurricane forecaster.
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Ally: What do you see as the impact on global weather and climate from
global warming?
Gray: We may have had a little bit of global warming the last century, maybe
1º Celsius or so but the warming seen is likely due to natural changes so
that we could know human beings are not affecting much.
I am very much a skeptic of these big global models that are running. I don't think they have the convective activity well and they
don't have the
ocean circulation in well. So we have seen a little warming over the last
century but if you look from 1945 up to the present time, there hasn't been
any warming because we had a cooling from 1940 to 1945 down to the early
1970s. Then from the early 1970s there been this warming.
I personally believe that in a few years we will see some slight global
cooling will take place because the ocean circulation patters are changing,
so most of the people that are pushing this global warming issue have very
little background in how the hydrologic cycle works and it's been much
oversold. I think your greatest worry in Barbados is from nature itself, not
from human beings altering nature.
There has been a slight ocean rise but that is probably natural. That is
very small. It's running at a rate or perhaps 10 centimetres per century.
There is nothing we can do about this. I don't think human beings, although
they are causing great environmental degradation in various places - cutting
forests down, pollution -, I don't think we are having much effect on
altering global temperature. What we've seen is almost totally natural
change that would have occurred whether the industrial world was putting
these pollutants into the atmosphere or not. So I would tell people in
Barbados to worry about real natural things.
You have hurricanes, flash floods, you have dust coming in from Africa. Do
not be diverted by these global warming arguments.
Ally: The IPCC has published persuasive-looking graphs. One on the quantity
of carbon into the atmosphere; the rate of increase in emissions doubled
what it was last century. There are 1600 scientists on the IPCC, can 1600
scientists be wrong?
Gray: In science the majority is often wrong, that's for sure. Of those 1600
scientists how much do they know of the hydrologic cycle? You can go pull
100 Nobel Laureates out of the closet and they will say that this is a
pretty important topic but they are brilliant in their own field - physics
and chemistry and other things - but they don't know much about the
hydrologic cycle.
The people who are pushing this the most are usually government officials,
bureaucrats who don't have a background to say this.
There is also the evidence from the satellites since 1979 which shows no
warming at all when they use measurements and it is conflicting with surface
reports. It is the surface over land that this is showing this warming and
primarily as a rise in the lowest temperature over land and it is
controversial. Why does satellites show no warming and the surface
measurement shows some warming?
We have a hypothesis that perhaps we had a lot more El Niños in recent years
and they've been stronger and we had more rain over the Pacific Ocean and
the land areas had slightly less rain and that incoming solar energy, rather
than going to evaporate vapours is going to warm the surface. It is very
controversial, and the more we go with it the more problems we will find in
it.
My personal view is that in the next 20, 30 years this warming will not keep
going and we will see slight cooling because the ocean currents dictate this
the most. They alter things and the hemispheric circulation responds to
that. For instance, what causes the cooling? People say the Earth warmed up
tremendously in the 1920s and 1930s, up to the early to middle 1940s and
cooled to the middle 1970s. We were burning fossil fuels then why did it
cool? They have never been able to explain that cooling. I think a cooling
trend like that will manifest itself in five or 10 years.
Ally: What is your hypothesis as to why that cooling will take place in
coming years?
Gray: Well, it is the same as what caused the cooling from the early 1940s
to the early 1970s. It is that the ocean currents change and we get a
response of the circulation from that. It doesn't cause warming, it causes
cooling.
In time, 20 or 30 years, I will not be here but, when they look back on it
they will see that it has been grossly exaggerated. We have so many other
problems in the world, this is something that is getting more attention than
it deserves. We have population problems, poverty, disease, crime, and
environmental problems and with this global warming thing you are taking
attention away from the local environmental problems that have to be dealt
with. Tremendous money is going into this. There are 30-something models modeling
this.
I've been studying the hydrologic cycle all my career and this is the
Achilles Heel. They do not understand how that as the hydrologic cycle picks
up they have middle and upper level water vapour in cirrus clouds getting
greater that blocks IR loss. See people don't understand that it is not the
carbon dioxide build up itself that causes warming. That causes some slight
warming but it is the feedback.
What the models have is this positive feedback. As the carbon dioxide goes
up, that causes the hydrologic cycle to work a little stronger and in a way
to put more water vapour and cirrus in and blocks more IR loss to space and that's the main effect. Our studies indicate
it's not a positive feedback.
As the hydrologic cycle speeds up you have the more intense clouds but you
have more sinking motion around the clouds and this will slightly reduce the
upper level vapour and the cirrus clouds and increase IR loss to space and
there will be little warming.
I have a lot of colleagues that are older than I. The IPCC and the WMO gets
together and try to push something and people tat have contrary views are
not part of this. There are a lot of my older colleagues who have similar
views to me, perhaps they are a little less public at expressing them than I
am but there are a lot of skeptics out there. They are saying there are not.
Vice President al Gore, about 10 years ago, said there were only two
skeptics in the United States. Houghton has come out and said there were
only 10 skeptics in the world that are familiar with the problem that
disagree with it. That's wrong. There are a whole lot out there. The problem is, they do not
approach them for input.
I've been working in global climate and has been a
meteorologist for over 40 years. They wouldn't approach me. My views are not
solicited at all and I know other critics' views are not solicited at all.
And when you have these hearings in government they can arrange to invite
people to the hearings to tell them what they want to hear.
I am worried about the real problems - hurricanes. Barbados ad the Caribbean
have got to be worried about that, that is your biggest problem. Don't worry
about global warming. The seas are not going to rise and flood Barbados out
in the next millennium or hundreds of years but these storms can come in and
do tremendous damage to you.
Ally: Before we go to hurricanes, let me ask you, do you support President
Bush's stand to pull out of the Kyoto Protocol?
Gray: Yes I do. He is just saying he is not for implementing the Kyoto
Treaty. I think that's a wise move because the science isn't done. If you
cut emissions then undoubtedly the standard of living of the industrialised
world will go down. It won't expand and we are doing so much in medicine and
all kinds of things. The problem is that the Third World countries - China
and India - are not going to cut down on the fossil fuel unless the western
world cuts down a great deal and we might not have to.
You might have pollution in all those cities. Certainly there is great
pollution - LA, Denver - then work on those problems. Those are real
problems but this global warming is sort of a nebulous thing that we do not
know about and there isn't enough research and I am very much against
implementing a treaty to do it. The whole world will suffer because we won't
advance the standard of living, no new products and development will come
out as fast.
Now a lot of people believe in global warming because they are against
pollution and are environmentalists and they have a legitimate concern but
the environmental problem should be dealt with locally to solve them. You won't solve them by cutting down on global fossil fuel use, you have to do
other things.
So I am not anti-environmental. As scientists we need to tell the truth as
we know it and let the politicians worry about the consequences.
Ally: How then do you explain extreme weather conditions? Drought in the
southern USA and the southern Caribbean and unseasonal floods and storms in
Europe. Things seem topsy turvy, so what is the explanation?
Gray: They've always been topsy turvy. In the history of human kind
everybody has always said, you see the lifespan of people is not so long,
and everyone says "The weather is never like this it used to be" and that is
human nature.
Barbados gets a major storm and people say "ah, we never had a storm like
this in years, the weather's changing". No. it is not the weather changing.
It is the low probability manifesting itself. England has had a lot of rain
but if you look back in the records you will see periods where England has
had a lot of rain, 100 years ago, 150 years ago. There is always extreme and
unusual weather that has occurred in the past and occurred in the natural
way of things but people's knowledge of weather is limited but when you go
back in the records and check you often find the unusual event occurred.
They are just natural but they are low probability.
Barbados does not get hit by many hurricanes. You are fortunate, you are low
latitude. Now if you should get two or three storms hitting Barbados in the
next couple of years, and I am not saying that will happen, the people in
Barbados will start saying "see, the weather is changing, it is not like it
used to be".
It changed locally in those two or three years but it does not mean the
whole globe is changing, but people always say it is, that's human nature.
See also: