What inspired you to get into the field of Geoengineering?

A student wrote me and asked, “I am doing a biography speech about you for my speech class, and I was wondering if you could answer just a couple of questions for me, if possible. What inspired you to get into the field of Geoengineering? Did something happen in your life that made you realize this is what was important to you?”  This is what I wrote her in response:

Most things in life happen as an unpredictable consequence of personal preparation and random opportunities.

I had studied and worked as a climate scientist for over a decade before I started to consider geoengineering.

In 1998, I co-organized a meeting on energy system transitions towards an energy system that did not use the sky as a waste dump. We, or more specifically, my mentor, Marty Hoffert, invited Lowell Wood to speak about geoengineering. He had been working on geoengineering concepts, working with Edward Teller at Lawrence Liverrmore National Laboratory.

Lowell claimed, without much evidence, that putting particles in the stratosphere could return Earth’s surface environment closer to what it was before the dawn of the industrial revolution. David Keith and I and a few others in the audience said something to the effect of “Even if you could return globally averaged temperatures back to what they were, there would still be large changes in regional and seasonal climate.”

At that time, I too worked at Lawrence Livermore National Laboratory, but it was a 7000-person workplace and I had never met Lowell Wood. However, next door to my office there was a guy named Govindasamy Bala and he ran atmospheric climate models. My initial goal was to show that solar geoengineering wouldn’t work and there would be large regional and seasonal mismatches. We had no money to do this, so I told Bala that if he ran the climate model simulations, he could be first author on the resulting paper.

We did the simulations and lo and behold the model predicted that the solar geoengineering would work quite well, and do a good job of offsetting regional and seasonal climate changes. This result was largely due to the strong influence of sea ice on the climate system. If you can restore sea ice back to what it was, then much of the rest of the climate system is also restored. Ours was the first three-dimensional climate model simulation of solar geoengineering.

So, this has been much of my history in this field: We try to poke holes in the idea, because emotionally I don’t like the idea of intentionally manipulating Earth’s climate system, but each time we do a computer model simulation, the results suggest that solar geoengineering could offset most climate change for most people most of the time.

Over the past decade, many more people have entered this area. As a scientist, I try to be the first to do something in a research area and then move on to something else. So, now I am spending perhaps 10% of my time on this research area.

For example, the 1998 paper that came out of that meeting in Aspen, was the first peer-reviewed paper ever to compute how much carbon-emission-free energy we would need to stabilize atmospheric CO2 levels while providing enough energy to sustain economic growth. Of course, now, many people are doing such calculations.

I just got back from 2 months in the Great Barrier Reef, where we for the first time ever put a plume of CO2-enriched seawater across a natural unconfined patch of coral reef, and we measured how the CO2 caused the reef to grow more slowly. We will not repeat this work, but try to move on to the next creative idea.


A comment on the proposal to close Indian Point nuclear power plant

A journalist asked me to comment on the efforts by Governor Cuomo to close down the Indian Point nuclear power plant, outside of New York City. An edited form of my reply follows (image from http://www.elp.com):


I am a climate scientist with no particular expertise on things nuclear and little knowledge specific to individual power plants and little knowledge about the details of New York’s power supply system, so I am a loathe to comment on Indian Point and other matters with great specificity.

I do know that nuclear power has been one of the safest and most reliable, if not the safest and most reliable, forms of electricity generation operating over the last half-century — and this is taking the tragic accidents at Chernobyl and Fukushima into account.

Coal kills something like 3000 people every day, largely due to health effects of particulate emissions. More people die from every week from coal-electricity production than have ever died as a result of nuclear power. The airplane crash gets the news; people dying on the highway every day is a bit ho-hum.

That said, if you were siting a nuclear power plant today, I don’t think you would site it near a giant population center. That is just sensible risk management. The risks are already small, but why not make them even smaller?

If Indian Point is closed down what will take its place? Will it be better or worse? What will be built additionally? Today, the cheapest electricity from new builds is typically natural gas. It is clear that natural gas is much worse for the environment than nuclear power.

I went to high school in Yorktown Heights, New York, less than 10 driving miles from Indian Point. Back then, I felt tangible disquietude, afraid that at some point the nuclear core might melt down and expose me to lethal radiation. Now, I understand intellectually that the likelihood of me dying in an automobile accident was many many thousands of times greater than ever dying as a result of a meltdown at Indian Point. But would I put many many thousands of times more effort into avoiding automobile accidents than I would put into trying to reduce risk from Indian Point? No. The desire to close Indian Point is mainly an emotional response to not-easily-quantified threats beyond our control, and not primarily based on a rational risk assessment.

A friend of mine did a study of a wide range of risks, and he decided that one of the main things we could do to reduce real risk in our lives is to wear motorcycle helmets while driving cars. His wife told him that if he did that, she wouldn’t ride in a car with him. So, he drives without wearing a motorcycle helmet.

It is a difficult question: How much should public policy cater to fears that are in large part irrational, but which nonetheless make people uncomfortable? A role of government is to help people feel better. To what extent is it appropriate for governments to undertake costly actions that cater to people’s largely irrational fears? (Isn’t that exactly what we did in Iraq?)

Tough questions. No simple answers.

Bridging the urban-rural divide


How much of our political view is shaped by whether we come from an urban or rural environment?

If you come from a city, you understand that we all depend on each other. You interact with and come to appreciate people of all sorts of races and religions. You live and work and have become friends with people who have come from all over the world. You recognize that we need social institutions to do something about that psychotic homeless guy. You don’t want people walking around on your streets carrying guns. You are probably going to vote for Clinton.

If you come from the middle of no place, you probably feel like you made it as far as you did mostly because of your hard work. You probably interact with few people outside of your own ethnic group. You likely live and work mostly with people born near you live. You expect your neighbor’s family to deal with their crazy uncle. You want your gun so you can hunt and protect yourself, just in case. You are probably going to vote for Trump.


Democracy is supposed to be a system where government acts in the interests of the majority, while protecting the rights of the minority. But no major political party has, in living memory, worked to promote the interests of the majority of Americans.

One thing working people in both urban centers and the rural regions can agree on is that the major parties have concerned themselves primarily  with satisfying the short-term interests of their powerful and wealthy donors. The major political parties have been working in the interest of a narrow minority while trampling on the rights of the majority. We all have a right to share in prosperity.

No major political party has, in living memory, worked to broadly share the fruits of globalization, increased automation, or immigration. Broadly shared prosperity is in the long-term interest of nearly everyone, because stark inequality is not a foundation for sustained economic growth.

Our nation is in crisis. If we are to avoid fascism and tyranny, our political parties must become democratic parties and work to promote the interests of the majority.

We need to find a way to reach across that urban-rural divide. Maybe we can recognize that it might make sense for everyone to have a gun on a farm, but not on a city street. Maybe we can agree that our successes depend both on our own hard work and on being surrounded by functioning social institutions (schools, police, healthcare, etc). People working on farms and in cities can agree that when a job leaves for China, or a job is replaced by a machine, or taken by an immigrant, the displaced person still needs to share in the benefits of that globalization and automation and immigration. The benefits can’t all go to the wealthy few.

The crisis in American democracy is a consequence of an unnecessary conflict between the urban and the rural which is in turn a symptom of the widening gap between the rich minority and struggling majority. The primary problem for the average working person in America, whether they be urban or rural, is a lack of prosperity. The common foe is inequality. The common goal should be sharing the benefits of globalization, automation, and immigration.

The success of the American experiment depends on bridging the urban-rural divide.

Images from:
Population density and 2012 election results: http://davetroy.com/posts/the-real-republican-adversary-population-density
Average income between 1946 and 2008: http://www.cbpp.org/research/tax-data-show-richest-1-percent-took-a-hit-in-2008-but-income-remained-highly-concentrated

This little essay was prompted by a comment by Mike Pesca on The Gist: http://www.slate.com/articles/podcasts/gist.html

Managing Earth’s Future: Self-restraint for the common good?

I was asked to be on a panel at the 2016 Fall American Geophysical Union Meeting on Planetary Intelligence: Managing Earth’s Future. This is what I wrote as an abstract before realizing I was limited to 2000 characters. (This is >2100 without spaces.)


We are global in our impacts, yet local in our thoughts and feelings. The daunting challenge facing Homo sapiens is learning to cooperate at global scale for the common good.

For millions of years, our ancestors, like most animals, consumed the fruits of their labors, and little capital or infrastructure accumulated over the ages. This radically changed over the past centuries. Following the inventions of the loom and the steam-engine, we have been developing ever more efficient ways of generating consumer products. Critically, some of the wealth generated by these more efficient technologies was reinvested into additional capital infrastructure, such as factories and machines, thus expanding the capacity to offer goods and services to insatiable consumers. Some of this reinvestment, and technological innovation, was in technologies that extracted and transformed natural resources into valuable goods and services and also into dangerous pollution. Improvements in medical technologies led to quasi-exponential population growth, mirroring and multiplying the quasi-exponential growth in per capita consumption.

We are reaching a stage where this quasi-exponential growth is starting to reach boundaries, but these boundaries are not sending signals to the market that would allow a laissez faire approach to work.

The central question is: How can we continue improving the well-being of living people (at least), while diminishing material flows associated with environmental pollution?

Globally speaking, if we don’t place constraints on ourselves, nature will impose constraints on us. We can impose constraints on ourselves to protect us from what nature would otherwise to do to us.

To have a sustainable future, we would need to level off population at the lowest feasible level. The difference between a future population of 6 billion and a future with 16 billion is a half-child per family less-or-more than the central projection of demographers. Empowering women with education and technology has proven to be a most effective strategy at reducing population growth.

To have a sustainable future, we would need strong disincentives on environmental damage, especially on the production of long-lived wastes such as carbon dioxide. It is of course a huge political challenge to get such disincentives in place. If we fail to get these global guardrails established, planetary management will be largely reactive, driven by competition among those with incentive and power.

In a resource- and pollution-constrained world, technological innovation is the surest path to economic growth and improved well being for all, especially the poorest on this planet.

With better policies in place, we can look forward to a future of continuous innovation and ever-improving well-being, with stable populations and diminishing environmental impact.




Ordinary Miracles


Some have criticized Bill Gates for saying that ‘we need an energy miracle’, suggesting this will be interpreted as Bill Gates saying that we should do nothing but sit around and wait for a miracle to occur.  I cannot speak for Bill Gates, but I can talk about what I understand him to be saying.

We live in a world of wonder, surrounded by technological miracles. We are surrounded by technological inventions which, if they were shown to our hunter-gatherer forebears, would have been attributed to magic or some divine power instead of to the laws of physics.

When I look out the window, I look through something that is hard as rock, yet almost invisible. Our ancestors would likely look at this strange artificial rock as some sort of miracle. Put a metallic film behind this rock and it turns into a mirror – surely an invention that Narcissus would have found miraculous.

We are so accustomed to technological miracles that we fail to appreciate the wonder of the technological world around us. We hurtle down highways in tin cans moving at 80 mph. We get in a cylinder and fly through the air at 500 mph. Our hunter-gatherer ancestors would have considered these technologies miraculous.

Electricity is magical. How do these wires cause my refrigerator to cool, my microwave to heat, and my audio system’s speakers to vibrate? Surely, the ancients would have found these technologies miraculous.

I can pull a little slab out of my pocket and instantaneously talk to someone on the other side of the planet. I turn on the television and see before me imagines from long ago and far away — miraculous.

Vaccines prevent disease and antibiotics cure disease — miraculous technologies.

With anesthetics, someone can slice me open and I wouldn’t even feel it — surely a miracle.

Technological miracles surround nearly our every waking moment. These come not from divine intervention but through the innovative work of brilliant people. Technology regularly creates miracles. We can expect further investment in clean energy research and development to generate more miracles.

Arthur C. Clarke once wrote “Any sufficiently advanced technology is indistinguishable from magic.” When I hear Bill Gates talk about the need for miracles, I hear him talking about the need for technologies that would, to our ancestors, be indistinguishable from something produced by divine intervention. These kinds of innovations happen all the time.

Recently, Bill Gates has written:

Some people argue that deploying today’s technology and developing new ideas are competitors in a zero-sum game—that doing one means you can’t do the other. I disagree.  Successful industries that are built on innovation rely on both deploying the technology they have and developing the technology they need.

This framing seems just about perfect to me: “Deploy what we have, and develop what we need.” We have enough to start down the path, even if we don’t yet have what we need to reach our destination. When real technologies confront real barriers out in the field, problem solvers innovate new solutions and create technological miracles.

The controversy over Bill Gates’s use of the word ‘miracle’ to describe what is needed to solve the climate problem comes from people’s perception of miracles being something that happens rarely as a result of divine intervention. However, we can also perceive miracles as something that commonly happens as a result of hard work.

When Bill Gates says ‘We need an energy miracle’, he means that we need to work hard to create the technologies needed to provide everybody with abundant and affordable clean energy. Technology miracles are something we can anticipate if we put in the effort to create those miracles.

Perhaps it would have been better for Bill Gates to use some other word, but we should try to understand what he is trying to communicate, rather than fret about how he might be misunderstood.

Bill Gates recognizes the deployment and innovation go hand-in-hand. Innovation doesn’t happen in a vacuum. Innovation will only create the needed miracles if we begin to address the climate problem with urgency using the technologies we already have.

Ordinary miracles are an expected outcome of hard work by creative people. These ordinary miracles will help us to reach our climate goals.

Helping the oceans help us

The Intergovernmental Oceanographic Commission, a branch of UNESCO, graciously awarded me their Roger Revelle Medal on World Oceans Day, Wednesday, 8 June 2016, and asked me to present the Roger Revelle Memorial lecture at the UNESCO facilities in Paris to the delegations from participating governments.  A lightly edited form of the abstract I sent them follows.IMG_5815 (2560x1707)

Ocean acidification and other stressors on marine systems: How can we help the oceans help us?

Ken Caldeira, Carnegie Institution for Science, Stanford CA 94305 USA, kcaldeira@carnegiescience.edu

For all of human history, life in the oceans has greatly helped humans. Marine life not only provides humans with food, but also can build structures such as coral reefs that help protect coastlines. Living things in the ocean also play central roles in the global carbon cycle.

Life in the oceans is confronted with a wide array of direct human challenges: overfishing, farm runoff, coastal development, industrial pollution, and so on. In addition to these challenges, climate change is warming and further stratifying the upper ocean, reducing nutrient supply to the well-lit near-surface ocean. Further, when the ocean absorbs carbon dioxide from the atmosphere, the ocean becomes more acidic, and this increased acidity makes it more difficult for many marine organisms to build their shells or skeletons.

For most of human history, humanity has been a relatively small force on the planet. What we did didn’t matter very much for most natural systems. But since the industrial revolution, humanity has become a geologic force, affecting our planet with an intensity and scale that will be clearly visible to geologists in the distant future.

If we want to keep taking from the ocean, we will have to give something back. If the ocean is going to continue helping us, we will need to help the oceans.

After a brief survey of new challenges faced by the oceans, this talk will take a somewhat autobiographical walk through developing an understanding of ocean acidification. The story begins with a discussion of the extinction of the dinosaurs and what it tells us about the sensitivity of our coastal systems to changes in ocean chemistry. It then moves on to discuss how projected future changes in ocean chemistry compare with those of the ancient past – and the conclusion is that the changes we are inducing now are large even by geologic standards. I will close with a description of some field work we have been doing, studying coral growth in the Great Barrier Reef.

The central thing that we need to do to protect the ocean from ocean acidification and climate change is to convert our energy system into one that does not use the sea and sky as repository for our waste carbon dioxide – an energy system that does not depend on smokestacks or tailpipes.

But there is much we can do to help ocean ecosystems become more resilient to the changes that will occur. There are other things we can do to help the oceans help us.

We can get better at managing fishing, including establishing no-fish zones. We can work with farmers to control run-off, work with industry to identify and eliminate dangerous pollutants from the production system. We can develop our coasts sensibly, and recognize the value of building a sustainable relationship with the wild and untamed.




Writing an OpEd piece on ocean acidification for the Sydney Morning Herald

The organizers of the 4th  The Ocean in a High-CO2 World symposium asked me to write an OpEd piece for the Sydney Morning Herald.

The challenge was to write about ocean acidification in a scientifically accurate way but also in a way that would be understandable to the average reader of the newspaper. Also, I wanted to write something that the average person could relate to — to humanize the issue so it wouldn’t seem so abstract.

Furthermore, it being an editorial, I was encouraged to put forward my own political views in some sort of general way, but I wanted to be general enough that the conference organizers and attendees would feel comfortable with what I was saying.

Also, I wanted to avoid being overly depressing or disingenuously hopeful.

Further, I wanted it to have some structure and literary value — something I think I achieved in some parts but not in others. On top of all of this, I am trying to do too many things, so the piece had to be more-or-less written as a stream-of-consciousness, because I didn’t have time for wordsmithing.

The headline for the OpEd piece was from the editors at the Sydney Morning Herald, and was not my concoction.

Anyway, resisting the temptation to fine tune post-publication, here is what I came up with. (This is a first draft, except for correction of minor grammatical errors. There is a ‘the’ that should have been removed from the last paragraph. Both the word ‘real’ in the first paragraph and the ‘for it’ after ‘life and death’ should have probably been eliminated.)


Oceans bearing the brunt of relentless carbon emission

by Ken Caldeira (published in the Sydney Morning Herald, 2 May 2016)

Most people live on land where the oceans are little more than a blue expanse of imagination. Does what I do right here on my spot of dry earth really matter to the far away vastness of the real ocean?

On a cold morning, when my home heater kicks on, natural gas burns and a plume of carbon dioxide streams out of my chimney and into the sky. When I make my morning toast, there is a power plant somewhere providing electricity to my toaster that is burning gas or coal and releasing giant plumes of carbon dioxide into the air. Much of this CO₂ will remain in the atmosphere for many thousands of years.

This pollution has physical consequences for our climate system, but it also has chemical consequences for our oceans.

In the atmosphere, too much CO₂ can make the world uncomfortably warm and melt the giant ice sheets and so on. Bad stuff.

This year has been just about the worst ever for coral bleaching. CO₂ in the atmosphere has been making Earth hotter and this is causing coral reefs to bleach, causing many colonies to die.

Most of the carbon dioxide we release to the atmosphere will eventually be absorbed by the oceans. They have already absorbed about one-quarter of the CO₂ produced by industrial civilisation over the past couple of centuries, and this process is making them more acidic.

When CO₂ reacts with seawater, it forms an acid. In high enough concentrations, this acid can corrode shells and skeletons of many marine organisms. In lower concentrations, it can make it harder for an organism to produce its shell or skeleton, and this could in some cases tip the balance between life and death for it.

There has been plenty of carbon dioxide in the atmosphere in the ancient past, and corals and clams and so on did just fine. There are natural processes involving rivers and sediments that buffer ocean chemistry over periods of thousands or tens of thousands of years. But right now, the ocean chemistry is changing way too fast to be buffered by Earth’s natural cycles.

The problem for marine organisms isn’t so much where we are going but how fast we are getting there. If we would spread out the emissions over tens of thousands of years instead of a few centuries, natural cycles would buffer the effects on ocean chemistry and there would be little to worry about. But if we do not dramatically reduce our rate of CO₂ emission, we will make the biggest and most rapid change in ocean chemistry the world has seen in many tens of millions of years – long before there were any humans on this planet.

We recently conducted experimental work in the Great Barrier Reef, providing evidence that ocean acidification is already slowing growth of the coral reef we examined. Increased stress from ocean acidification is probably making corals less able to stand up to heat stress and so contributing to coral bleaching. We have also made careful observations of tide pools along California’s coast, and the organisms there also seem to be affected by changes in ocean chemistry.

As a scientist, I work to better understand the relationships between our actions and what happens in the real world. On a chilly morning, I heat my home and make myself some toast and coffee, and sink into my easychair. I understand that in doing this I am contributing to killing off coral reefs and that I am affecting other marine ecosystems in unimagined ways. We know that protecting the oceans means we need, among other things, to stop using the atmosphere as a waste dump for our carbon dioxide pollution. We need to stop building things with smokestacks or tailpipes.

Scientific understanding is the cornerstone of good public policy. Science can never tell us what to do, but it can give us an idea of what might happen if we choose different courses of action. An intensified effort to develop the scientific knowledge can help us better understand the consequences of our choices. And we, as a society, can choose wisely.