Dr. Nicholas Gruber, Prof. of Environmental Physics Discusses the Earth's Natural Cycles   Part 1
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Part 1
Greetings and welcome to Planet Earth: Our Loving Home. Today, we speak with Dr. Nicolas Gruber, a professor of Environmental Physics at the Swiss Federal Institute of Technology Zurich (ETH), based in the beautiful country of Switzerland.

He earned his Ph.D. at the University of Bern in Switzerland, and thereafter worked as a postdoctoral researcher at Princeton University in the United States. Dr. Gruber had also worked in the Department of Atmospheric and Oceanic Sciences and the Institute of Geophysics and Planetary Physics at the University of California, Los Angeles (UCLA).

For more information on Dr. Nicolas Gruber, please visit: www.up.ethz.ch/people/ngruber

 Dr. Nicolas Gruber:
The atmospheric greenhouse effect is very vital for planet Earth. Without greenhouse gases in the atmosphere, Earth would not be a habitable planet, actually, for human life. If we took out all the greenhouse gases from the atmosphere, Earth’s temperature would be about -15oC.

Dr. Nicolas Gruber:
It would be a frozen planet. So there are a number of greenhouse gases that are important and have essentially made Earth a habitable planet; that is, have raised the temperature from this -15 to about the temperature of about 15oC, which is the global average temperature right now.

The most important greenhouse gas that there is, is water vapor. Then there are other greenhouse gases like CO2, which is the second most important, carbon dioxide. There is methane, there is nitrous oxide and there’s a bunch of other gases that are in the atmosphere.

The way greenhouse gases work is that they are transparent to the incoming light from the sun. The sun emits energy at the range of the wave spectrum that is visible to the eye and that’s why we see light.

These gases are like a window pane so the sun can come in. The sun then heats the surface of the atmosphere. The earth’s surface, once it has a certain temperature, it starts to emit energy to the outside world.

And it emits this energy at our temperatures, not in the visible range but in another range, which is the infrared.

But now that we have these greenhouse gases in the atmosphere and while they are transparent for the incoming light, they are not transparent for this outgoing infrared radiation.

So they trap this energy and thereby heat up the lower parts of the atmosphere.

That’s what we call the natural greenhouse gas effect.


In the natural cycle, the greenhouse gas effect is beneficial, even necessary for human life. However, human activities have caused a major disturbance to the balance of this cycle.

Dr. Nicolas Gruber:
What we have done in the last couple of hundred of years, we have increased the atmospheric CO2 concentration in the last couple of hundred years by more than thirty percent.

Thirty percent!

Dr. Nicolas Gruber:
That additional CO2 has now increased this greenhouse effect. That increase is what we call the anthropogenic, the human-induced greenhouse gas effect.

Let’s focus on carbon dioxide.

Could you give us a brief but quantitative descript-xion of global circulation of carbon dioxide? And specifically what happens to the CO2 portion that we humans emit into the atmosphere?

Dr. Nicolas Gruber:
The carbon cycle on Earth is a very dynamic cycle. If we are mainly concerned with the systems that are circulating carbon within a time scale of a couple thousand years, the most important players that we have are number one, the ocean.

Number two, we have carbon stored in plants on land, also in the soil on land.

And then the third component in the system is the atmosphere.

Let’s take a look at how these reservoirs are connected to each other. So carbon can be exchanged very readily between the ocean and the atmosphere. So a molecule of carbon dioxide which sits in the ocean can leave the ocean, go to the atmosphere.

At the same time a molecule of CO2 in the atmosphere can cross the Earth-sea interface and go into the oceans. And there’s constantly a change, a flux of carbon going from the atmosphere to the ocean and back.

Something similar is happening on the land where a molecule of CO2 in the atmosphere can be taken up by plants.

That’s as part of a normal, regular process. It’s called photosynthesis.

And what they do, they take that carbon dioxide and build plant tissues. So they build leaves, they build trunks of the trees, stems. And when the leaf has fallen off then it goes to the ground and slowly decomposes.

During this decomposition process the carbon dioxide, and the carbon that was stored in the leaf is then slowly going back into the atmosphere.

So there is another flux of carbon dioxide from the atmosphere to the land biosphere, to the plants and soils, and then from the plants and soils back into the atmosphere.

And these exchanges are actually rather large. A lot of carbon is being turned around and is being exchanged. Now let’s also look at how much carbon is actually within these individual systems.

By far the largest amount is actually stored in the ocean. The unit that we usually talk about is petagrams of carbon; in terms of amount of carbon, we have about 40,000 units of carbon in the ocean.

And then we have in pre-industrial times, before humans really started to change things, we had about 600 units in the atmosphere, and we had about 3,000 units in the terrestrial biosphere, so that means the atmosphere contains only about 1/60, so a very few percent of the amount that’s actually stored in the ocean.

So we have a system that is readily exchanging, but all of these exchanges have been pretty much in balance. The same amount that has gone from the atmosphere into the ocean has been returned from the ocean to the atmosphere.

And the same is true on the terrestrial biosphere.

How did human activity over the past three hundred years disrupt the global carbon cycle, and what are the consequences?

Dr. Nicolas Gruber is a professor of Environmental Physics from the Swiss Federal Institute of Technology.

In 2004, Dr. Gruber was awarded the Rosenstiel Award by the Rosenstiel School of Marine and Atmospheric Science of the University of Miami in Florida, USA for his achievements in marine sciences.

Thus far, he has published more than 50 papers in peer-reviewed journals and co-authored two books, including Ocean Biogeochemical Dynamics, a text that has attracted great interest and acclaim.

Dr. Gruber explains how human activities have caused an unbalance in the natural carbon cycle.

Dr. Nicolas Gruber:
We started to take fossil carbon, that’s coal, primarily in the old days; now it’s much more natural gas and petrol, and we have started to take this and we burn that fossil fuel. And when that fossil fuel is burned, it produces CO2.

That CO2 is then going into the atmosphere. So suddenly we have a system that works normally and now we suddenly start to change that.

And to disturb it.

Dr. Nicolas Gruber:
This disturbs that system. By now we know very well that about half of these emissions stay in the atmosphere.

About 30% of these emissions are being taken up by or even a little bit more, 35% are being taken up by the ocean. And about 15 %, sometimes 20% are being taken up by the terrestrial biosphere.

So the ocean and the terrestrial biosphere have helped us to reduce the loading of CO2 in the atmosphere.


Dr. Nicolas Gruber:
But nevertheless, the other half has stayed in the atmosphere and as a result of that, the atmospheric CO2 concentration has increased over the last 250 years by more than 30%.

Dr. Nicolas Gruber:
We have analyzed the temperature trends and how they have changed through time, and have compared them with our expectations based on the changes in the atmospheric CO2 concentration and the concentration of other greenhouse gases.

We’ve been able to say with a lot of confidence, and the IPCC (Intergovernmental Panel on Climate Change) said that confidence is now more than 90% that this increase in greenhouse gases in the atmosphere has been the cause for the changes in atmospheric temperatures, which was nearly a degree Celsius by now, not quite, but soon, about a one-degree change over the last 200 years.

Through recent research on the greenhouse effect, including the application of the isotope analysis method, scientists have achieved an in-depth understanding of the variations in atmospheric carbon dioxide concentrations through history.

Dr. Nicolas Gruber:
Carbon comes sort of in different flavors. We can think of green, red and yellow flavors.

There’s Carbon 12, there’s Carbon 13 and there’s Carbon 14, and Carbon 14 is also called radiocarbon. The interesting thing about radiocarbon is that it’s radioactive so it decays through time. And the half-life of C14 is such that fossil fuels which have been produced many, many millions, millions of years ago do not contain any C14 anymore.

All of the C14 that was present originally has decayed away. So we’re burning fossil fuel that has essentially no C14 and we add that CO2; it just has C12 and C13, it’s just red and green.

Hence the concentration of the relative concentration, C14 relative to the total, C14 has decreased through time so that’s one piece of evidence.

We can do something similar with Carbon 13 and more or less using the same argument. And then the third line of evidence that shows the CO2 increase in the atmosphere is man-made, is essentially just by looking at the budgets.

If we look at the budgets and we look how much carbon is where, then we know pretty well how much carbon we’ve burned over the last couple of centuries and then we know pretty well how much carbon there is in the atmosphere and how much that has changed through time.

We have good records, we have direct measurements for more than 50 years now from Mauna Loa; it’s a site in Hawaii and many other places around the planet and we have good reconstructions of the atmospheric CO2 content based on an ice core, so we can extend the record backwards in time.

In addition, we also have good measurements of the carbon content of the ocean, and we also have measurements now which demonstrate how this has been changing through time.

We don’t find evidence of a massive loss of carbon from the ocean that would have driven the atmospheric increase. Instead what we find is an increase of the CO2 content in the ocean.

So the ocean has actually taken up carbon from the atmosphere, so we don’t find a magical source of carbon that would have caused that increase in the atmosphere; there is no magical source.

What we do know is that we have burned fossil fuels, a great amount of fossil fuel, and half of those have remained in the atmosphere and the other half has been taken up by the ocean and the land and there is very little doubt about that.

It’s indeed the fact that the present concentration, with about 300 parts per million, is higher than anytime in the last, almost a million years, by now.

About a couple of months ago, a new paper was published that was able to extend the ice-core record backwards in time from 650,000 years ago to about 850 to 900 thousand years ago. And also in that part of the record, the CO2 concentration was considerably lower than today.

We have seen about almost ten ice ages since then; that’s a long time, that’s much, much longer than our species has been present on this planet.

So we’ve really changed things dramatically.

Tune in next Wednesday to Planet Earth: Our Loving Home for the continuation of Dr. Nicolas Gruber’s interview in which he will discuss the latest scientific research findings as well as his opinions on how to curb global warming.

Part 2

Dr. Nicolas Gruber:
Climate has always changed. We have plenty of evidence in the geological record. Temperatures during the ice age were significantly colder than now.

We had these huge glaciers, the poles, particularly the North Pole was covered in a really huge ice sheet; northern Europe was covered with a huge ice sheet; the whole North America, the northern part of North America was covered with an ice sheet.

So climate was really different. The maximum of that was about twenty thousand years ago. What is different from these past changes are two things.

The first thing is that we’re pretty confident that the changes we have observed in the last two hundred years, and particularly, actually in the last 50, 30 years, are man-made.

Secondly, it’s the speed, how fast climate has been changing is, and particularly how fast atmospheric CO2 has been changing is unprecedented, at least in what we know from the past.

We’re changing the pace of these systems. Just an example: twenty thousand years ago, I mentioned we were in an ice age.


Dr. Nicolas Gruber:
It took several thousand years for the climate to transition out of this last glacial maximum into the present Holocene.

There were some faster variations in between but the overall big change took several thousand years.

Whereas the climate change that we’re talking about right now is occurring on a time scale of decades to centuries.

It makes it dangerous and it makes it something that we have to do something about.

The areas where we have seen the largest changes and the fastest changes in the last couple of decades were actually the high northern latitudes, places like Siberia, places like Alaska, northern Canada. And those places have really, really rapidly warmed.

So while the global average temperature has changed a little bit less than one degree, those places have changed about twice or three times that amount just in the last 30 years.

And permafrost is thawing.

Dr. Nicolas Gruber:
Permafrost is thawing, and those changes have had huge impacts on ecosystems.

Dr. Nicolas Gruber:

As the permafrost is thawing, water, that’s water that’s frozen is put down into the system and so you have suddenly soils that are water clogged and did not used to be water clogged.

You have trees that suddenly have had their roots in the solid ground and as the permafrost is thawing, they fall over.

In Europe what was investigated were grasses and flowers; they’ve actually been migrating upwards in the Alps. A particular species of flower that was not able to flower above eleven hundred meters is suddenly now able to flower at twelve hundred meters.

They have been able to migrate upwards and so that has been documented.

And literally myriads of changes in ecosystems all across the globe have been able to demonstrate the changes. We’ve seen changes in the physical world, for example, glaciers. We’ve seen the retreat of large glaciers. We’ve seen changes in precipitation. We’ve seen changes in landslides.

A lot of effects we think are just going to be increasing so as the more it warms, the stronger these impacts get. That’s one aspect. The other aspect, and that’s really the one that we’re really concerned about, are when the system does not behave linearly anymore.

What we call a linear response is you push the book here and it just goes over and over. But there’s a point where the book comes here to the edge and then it will tip over.

So we call them “tipping points.” A particular species can only tolerate a particular temperature, and if you go above a certain temperature, it just simply dies because of heat and, or other chemical processes that are also strongly dependent on the environment.

And there could be circulation patterns in the ocean that could suddenly change dramatically as a result of global climate change.

Some of these transitions might be irreversible. A big challenge for us researchers is that we often don’t quite know where these tipping points are.

Dr. Gruber explains how the nature of the feedback cycle exacerbates global warming.

Dr. Nicolas Gruber:
The ocean and the land biosphere are taking up CO2 from the atmosphere, about half of how much we have emitted, but we are concerned now that global climate change is going to change that, so that suddenly the ocean and the land are no longer going to be taking up half, perhaps only a quarter.

So of all the emissions we put in the atmosphere, that three quarters is going to stay in the atmosphere, then the CO2 in the atmosphere will increase faster, cause more global warming and the warming will again reduce the amount of CO2 being taken up by the ocean and the land, and put even more CO2 in the atmosphere.

That would lead to additional warming.

How should all of us act to reduce global warming?

When Planet Earth: Our Loving Home returns, Dr. Gruber will share his suggestions on this issue. Please stay tuned to Supreme Master Television.

Welcome back Planet Earth: Our Loving Home for our exclusive interview with Dr. Nicolas Gruber, professor of Environmental Physics from the Swiss Federal Institute of Technology.

Dr. Gruber gives his suggestions on how to curb global warming.

Dr. Nicolas Gruber:
What we have to do is we have to start acting today.

And an analogy that I often use is like a supertanker; a supertanker moves in the water and it’s being propelled forward.

But if you want to change the direction, if you want to stop the supertanker, it’s not something you can do immediately.

If you want to ensure that the supertanker does not run into another ship five kilometers down the road, you sort of have to turn the engine and reduce the speed, or put the engines in reverse now so that the supertanker starts to slow down.

And I think that’s what we’re talking about right now.

Do you find that governments are actually listening now to scientists?

Dr. Nicolas Gruber:
I do think so, increasingly so.

I think the whole process of the Intergovernmental Panel on Climate Change (IPCC), which was rewarded the Nobel Peace Prize last year.

Yes, we interviewed him in Geneva, Dr. Pachauri.

Dr. Nicolas Gruber:
Dr. Pachauri, of course, as the head of the IPCC.

I was myself involved in writing this report, one of those in 2000 or so that was given the Nobel Peace Prize. This IPCC report, has really been taken seriously, very seriously by many nations.

So, I think there has been a very significant change in the way the political world is perceiving the issue.

What action would you recommend that people and governments should take to limit the global warming effects in order of priorities?

Dr. Nicolas Gruber:
In order to stabilize climate, we have to stabilize the atmospheric CO2 concentration and the concentration of all greenhouse gases.

The big challenge that we have is how are we going to reduce our CO2 emissions. The reason that we are emitting CO2 is because we’re using fossil fuels.

Dr. Nicolas Gruber:
We’re using energy for producing the goods, the papers, heating, cooling, everything. It’s such an intricate part of our industrial world that it is not something that we can easily change.

We have to work at a large number of levels.

One thing we can start to do is we can start to become more energy efficient.


Dr. Nicolas Gruber:
Just reduce the energy in every aspect whatever we use energy, that helps.

Then we can reduce the amount of fossil fuels that we use to produce energy.

So that means we can substitute energy production systems that emit CO2 with such that don’t emit CO2. For example, we could use wind power to produce electricity instead of using a coal-fired power plant, use one that burns natural gas.

Or solar energy?

Dr. Nicolas Gruber:
Or we can use solar energy.

We can use in some respects, we can use biomass. They are emitting much, much less CO2
in the whole life cycle.


Dr. Nicolas Gruber:
We have to substitute essentially our reliance on fossil fuels to produce energy. So that’s number two.

And then the third issue on that, we can try to use ways to actually take out CO2 from the atmosphere; for example, increase the amount of forest that we have.

Or at least protect the forest that we do have and that also helps.

We shouldn’t wait any longer but start to increase the use of the alternative energy, increase the making of all procedures, everything more energy efficient and work and bring these forward at the same time and hope that the climate will not hit us with something unpredictable at the moment in the meantime.

Dr. Nicolas Gruber:
There are a lot of little things that we can do individually.

But I always emphasize that I think it's important and necessary, but it's not sufficient. I mean we have to work at all levels, I mean not just at the individual level but also at the level of how industries organize, how nations organize, etc.

Yes. We are actively involved in a campaign to change people's way of living. We very much ask people to eat, for example, less meat because we found out that methane gas is much worse for the environment than CO2 and that, for example, livestock raising produces an enormous amount of methane gas, as well of course, producing CO2 by transport.

In principle, it should be easier to implement vegetarianism than, for example, replacing fossil fuels by renewable energy sources faster because vegetarianism comes with a personal decision, just like stopping the habit of smoking, for example. 

We believe that automatically, and other means for solving energy problems will be easier to implement if necessary.

Do you agree that without raising human consciousness it would be difficult if not impossible to solve problems coming from global warming? 

Dr. Nicolas Gruber:
I think consciousness is very important.

It's the beginning and the absolutely necessary beginning for making changes, of the people and governments and industries.

Any organization is not ready to make a change unless you have come to realize that this is something that one should act upon.

So raising awareness and consciousness is absolutely important.

Moving from meat to essentially to eating vegetarian, there are certain elements that you can do to the environment that is actually beneficial. The human consumption of meat has increased considerably in the last couple of decades, and that is actually causing some environmental problems.

From an overall environmental point of view, reducing meat consumption is a good thing.

A lot of the rainforests in Brazil are cut to get food for cattle. So that's a very big environmental problem. 

Dr. Nicolas Gruber:
Yes. I'm mostly vegetarian, myself. That helps essentially to protect the rainforest.

We thank Dr. Nicolas Gruber for his diligent work in studying the effects of climate change. Our best wishes to him for continued success in his noble endeavors.

For more information on Dr. Nicolas Gruber, please visit: www.up.ethz.ch/people/ngruber