Today I testified to Congress about global warming, 20 years after my June 23, 1988 testimony, which alerted the public that global warming was underway. There are striking similarities between then and now, but one big difference.
Again a wide gap has developed between what is understood about global warming by the relevant scientific community and what is known by policymakers and the public. Now, as then, frank assessment of scientific data yields conclusions that are shocking to the body politic. Now, as then, I can assert that these conclusions have a certainty exceeding 99 percent.
The difference is that now we have used up all slack in the schedule for actions needed to defuse the global warming time bomb. The next president and Congress must define a course next year in which the United States exerts leadership commensurate with our responsibility for the present dangerous situation.
Otherwise it will become impractical to constrain atmospheric carbon dioxide, the greenhouse gas produced in burning fossil fuels, to a level that prevents the climate system from passing tipping points that lead to disastrous climate changes that spiral dynamically out of humanity's control.
Changes needed to preserve creation, the planet on which civilization developed, are clear. But the changes have been blocked by special interests, focused on short-term profits, who hold sway in Washington and other capitals.
I argue that a path yielding energy independence and a healthier environment is, barely, still possible. It requires a transformative change of direction in Washington in the next year.
On June 23, 1988 I testified to a hearing, organized by Senator Tim Wirth of Colorado, that the Earth had entered a long-term warming trend and that human-made greenhouse gases almost surely were responsible. I noted that global warming enhanced both extremes of the water cycle, meaning stronger droughts and forest fires, on the one hand, but also heavier rains and floods.
My testimony two decades ago was greeted with skepticism. But while skepticism is the lifeblood of science, it can confuse the public. As scientists examine a topic from all perspectives, it may appear that nothing is known with confidence. But from such broad open-minded study of all data, valid conclusions can be drawn.
My conclusions in 1988 were built on a wide range of inputs from basic physics, planetary studies, observations of on-going changes, and climate models. The evidence was strong enough that I could say it was time to "stop waffling." I was sure that time would bring the scientific community to a similar consensus, as it has.
While international recognition of global warming was swift, actions have faltered. The U.S. refused to place limits on its emissions, and developing countries such as China and India rapidly increased their emissions.
What is at stake? Warming so far, about two degrees Fahrenheit over land areas, seems almost innocuous, being less than day-to-day weather fluctuations. But more warming is already "in the pipeline," delayed only by the great inertia of the world ocean. And climate is nearing dangerous tipping points. Elements of a "perfect storm," a global cataclysm, are assembled.
Climate can reach points such that amplifying feedbacks spur large rapid changes. Arctic sea ice is a current example. Global warming initiated sea ice melt, exposing darker ocean that absorbs more sunlight, melting more ice. As a result, without any additional greenhouse gases, the Arctic soon will be ice-free in the summer.
More ominous tipping points loom. West Antarctic and Greenland ice sheets are vulnerable to even small additional warming. These two-mile-thick behemoths respond slowly at first, but if disintegration gets well under way, it will become unstoppable. Debate among scientists is only about how much sea level would rise by a given date. In my opinion, if emissions follow a business-as-usual scenario, sea level rise of at least two meters is likely within a century. Hundreds of millions of people would become refugees, and no stable shoreline would be reestablished in any time frame that humanity can conceive.
Animal and plant species are already being stressed by climate change. Species can migrate in response to movement of their climatic zone, but some species in polar and alpine regions will be pushed off the planet. As climate zones move farther and faster, climate change will become the primary cause of species extinction. The tipping point for life on the planet will occur when so many interdependent species are lost that ecosystems collapse.
The shocking conclusion, documented in a paper2 I have written with several of the world's leading climate experts, is that the safe level of atmospheric carbon dioxide is no more than 350 ppm (parts per million), and it may be less. Carbon dioxide amount is already 385 ppm and rising about 2 ppm per year. Shocking corollary: the oft-stated goal to keep global warming less than two degrees Celsius (3.6 degrees Fahrenheit) is a recipe for global disaster, not salvation.
These conclusions are based on paleoclimate data showing how the Earth responded to past levels of greenhouse gases and on observations showing how the world is responding to today's carbon dioxide amount. The consequences of continued increase of greenhouse gases extend far beyond extermination of species and future sea level rise.
Arid subtropical climate zones are expanding poleward. Already an average expansion of about 250 miles has occurred, affecting the southern United States, the Mediterranean region, Australia and southern Africa. Forest fires and drying-up of lakes will increase further unless carbon dioxide growth is halted and reversed.
Mountain glaciers are the source of fresh water for hundreds of millions of people. These glaciers are receding world-wide, in the Himalayas, Andes and Rocky Mountains. They will disappear, leaving their rivers as trickles in late summer and fall, unless the growth of carbon dioxide is reversed.
Coral reefs, the rainforest of the ocean, are home to one-third of the species in the sea. Coral reefs are under stress for several reasons, including warming of the ocean, but especially because of ocean acidification, a direct effect of added carbon dioxide. Ocean life dependent on carbonate shells and skeletons is threatened by dissolution as the ocean becomes more acid.
Such phenomena, including the instability of Arctic sea ice and the great ice sheets at today's carbon dioxide amount, show that we have already gone too far. We must draw down atmospheric carbon dioxide to preserve the planet we know. A level of no more than 350 ppm is still feasible, with the help of reforestation and improved agricultural practices, but just barely -- time is running out.
The steps needed to halt carbon dioxide growth follow from the size of fossil carbon reservoirs. Coal towers over oil and gas. Phase out of coal use except where the carbon is captured and stored below ground is the primary requirement for solving global warming.
Oil is used in vehicles, where it is impractical to capture the carbon. But oil is running out. To preserve our planet we must also ensure that the next mobile energy source is not obtained by squeezing oil from coal, tar shale or other fossil fuels.
Fossil fuel reservoirs are finite, which is the main reason that prices are rising. We must move beyond fossil fuels eventually. Solution of the climate problem requires that we move to carbon-free energy promptly.
Special interests have blocked transition to our renewable energy future. Instead of moving heavily into renewable energies, fossil companies choose to spread doubt about global warming, as tobacco companies discredited the smoking-cancer link. Methods are sophisticated, including disguised funding to shape school textbook discussions.
CEOs of fossil energy companies know what they are doing and are aware of long-term consequences of continued business as usual. In my opinion, these CEOs should be tried for high crimes against humanity and nature. If their campaigns continue and "succeed" in confusing the public, I anticipate testifying against relevant CEOs in future public trials.
Conviction of ExxonMobil and Peabody Coal CEOs will be no consolation, if we pass on a runaway climate to our children. Humanity would be impoverished by ravages of continually shifting shorelines and intensification of regional climate extremes. Loss of countless species would leave a more desolate planet.
If politicians remain at loggerheads, citizens must lead. We must demand a moratorium on new coal-fired power plants. We must block fossil fuel interests who aim to squeeze every last drop of oil from public lands, off-shore, and wilderness areas. Those last drops are no solution. They provide continued exorbitant profits for a short-sighted self-serving industry, but no alleviation of our addiction or long-term energy solution.
Moving from fossil fuels to clean energy is challenging, yet transformative in ways that will be welcomed. Cheap, subsidized fossil fuels engendered bad habits. We import food from halfway around the world, for example, even with healthier products available from nearby fields. Local produce would be competitive if not for fossil fuel subsidies and the fact that climate change damages and costs, due to fossil fuels, are also borne by the public.
A price on emissions that cause harm is essential. Yes, a carbon tax. Carbon tax with 100 percent dividend is needed to wean us off fossil fuel addiction. Tax and dividend allows the marketplace, not politicians, to make investment decisions.
Carbon tax on coal, oil and gas is simple, applied at the first point of sale or port of entry. The entire tax must be returned to the public, an equal amount to each adult, a half-share for children. This dividend can be deposited monthly in an individual's bank account.
Carbon tax with 100 percent dividend is non-regressive. On the contrary, you can bet that low and middle income people will find ways to limit their carbon tax and come out ahead. Profligate energy users will have to pay for their excesses.
Demand for low-carbon high-efficiency products will spur innovation, making our products more competitive on international markets. Carbon emissions will plummet as energy efficiency and renewable energies grow rapidly. Black soot, mercury and other fossil fuel emissions will decline. A brighter, cleaner future, with energy independence, is possible.
Washington likes to spend our tax money line-by-line. Swarms of high-priced lobbyists in alligator shoes help Congress decide where to spend, and in turn the lobbyists' clients provide "campaign" money.
The public must send a message to Washington. Preserve our planet, creation, for our children and grandchildren, but do not use that as an excuse for more tax-and-spend. Let this be our motto: "One hundred percent dividend or fight! No more alligator shoes!"
The next president must make a national low-loss electric grid an imperative. It will allow dispersed renewable energies to supplant fossil fuels for power generation. Technology exists for direct-current high-voltage buried transmission lines. Trunk lines can be completed in less than a decade and expanded analogous to interstate highways.
Government must also change utility regulations so that profits do not depend on selling ever more energy, but instead increase with efficiency. Building code and vehicle efficiency requirements must be improved and put on a path toward carbon neutrality.
The fossil-industry maintains its stranglehold on Washington via demagoguery, using China and other developing nations as scapegoats to rationalize inaction. In fact, we produced most of the excess carbon in the air today, and it is to our advantage as a nation to move smartly in developing ways to reduce emissions. As with the ozone problem, developing countries can be allowed limited extra time to reduce emissions. They will cooperate: they have much to lose from climate change and much to gain from clean air and reduced dependence on fossil fuels.
We must establish fair agreements with other countries. However, our own tax and dividend should start immediately. We have much to gain from it as a nation, and other countries will copy our success. If necessary, import duties on products from uncooperative countries can level the playing field, with the import tax added to the dividend pool.
Democracy works, but sometimes churns slowly. Time is short. The 2008 election is critical for the planet. If Americans turn out to pasture the most brontosaurian congressmen, if Washington adapts to address climate change, our children and grandchildren can still hold great expectations.
Dr. Hansen, this topic is well outside your personal sphere of expertise. Upon what basis is this statement made? Other, actual experts in this field are far less certain than you, describing the effect as "largely unknown":
"Although the changes in ocean acidity can be pre-dicted with great certainty, the consequences for marineorganisms, their ecosystems and climate-relevant organicgas emissions are largely unknown"
source: http://64.233.169.104/search?q=cache:5T6U-Kp84VkJ:infohost.nmt.edu/~chem/wingenter/Wingenter_PeECE_III_GRL_2007.pdf+ocean+ph+paleohistory&hl=en&ct=clnk&cd=2&gl=us
Think carefully: if you knew that there was a 50% chance that you and your family would become homeless beggars due to a certain course of action, wouldn't you change that course of action? What if the best scientific minds took decades of data and said there is over a 90% chance that we are causing permanent (within any time span that matters to us) damage to the planet? Would you make an effort to lower carbon and other greenhouse gas emissions? Would you encourage electric cars, and even better communities that support walking, bicycles, and mass transit? Would you not join with neighbors and your country to change policies? Maybe not - because of deep, unconscious attachment to material, unlimited "growth" which is without realizing it, a self-destructive addiction. We need to break that addiction and move forward to a safer world!
Did I miss something here? Acid-base reactions are a subject of first semester chemistry. Acids will work to destroy carbonate and CO2 is liberated into the atmosphere upon reaction. I don't see how it is a mystery that carbonate shells are threatened as oceans become more acidic. Any junior scientist can drop one drop of acid on carbonate shells or any carbonate rock and see the liberation of carbon dioxide in bubbles. Enlighten me on how carbonate shells could possibly be protected from acid in the ocean.
To give you some idea of the danger we face look at what happened just two hundred and fifty million years ago at the end of the Permian Age. This global warming event very nearly wiped out all life on this planet. Only small bivalves that lived in the mud at the bottom of rivers and a strange looking reptile named Lystrosaurus managed to survive, mainly because they were able to live in a low oxygen atmosphere. Global warming has proven to be very dangerous to life.
How ironic it would be if the most intelligent species on this planet allowed itself to become extinct because it lacked the wisdom to change its ways.
Thank you Dr. Hansen for your service to humanity.
It was nothing like the current discussion, which is based on the actual goings on. There are detailed discussions of all the distortions used by climate change deniers. The fact is that Dr. Hansen, and many others with less visibility in the United States, have been soberly and carefully examining a multitude of facts relating to climate history and current trends. They are quite intelligent, and the danger is a serious one.
It is, however, unpolitic to deal with such a reality, as it changes many relationships and the usual way of doing business and government. However, we must deal with it.
http://www.co2science.org/articles/V11/N27/EDIT.php
A critique of these recent rantings...
http://www.co2science.org/education/reports/hansen/hansen.php
Why doesn't someone compare that graph to what has actually happened through 2008 (based on data provided by his own GISS).
The results may surprise you:
http://www.dirckthenoorman.com/?p=948
No more drive thu's:
http://www.madison.com/tct/news/stories/293046
http://en.wikipedia.org/wiki/Global_warming
The driver for this problem has been found to be atmospheric carbon dioxide. The wikipedia.org has an excellent discussion of this under atmospheric carbon dioxide. It provides evidence that for 800,000 years Earth has between 180 ppm and 300 ppm of carbon dioxide in the atmosphere. In the last 200 years carbon dioxide has increased to 380 ppm and is forecast to go to over 500 to 900 ppm by 2100!
http://en.wikipedia.org/wiki/Atmospheric_carbon_dioxide
The effect of greenhouse gas effect was discovered in 1824 and is well understood. The greenhouse gas effect of carbon dioxide is well understood. The extra carbon dioxide will trap additional heat in the atmosphere and the earth will warm up.
David Wojick http://www.climatechangedebate.org
There are lots of year to year variations, both up and down, that exceed the average yearly increase. That doesn't disprove anything. There is still, on the average, a year to year increase, that is obvious to everyone.
Note the apparent increased rate of change of temperatures starting in 1960.
If you understand those facts, why is it a surprise that our carbon dioxide density is now warming the planet. It is not a surprise - but it is the conclusions that many of us, understandably but unacceptably, do not want to face. It is not unacceptable because we are in an "argument", but because the earth's environment needs our urgent action.
http://www.youtube.com/watch?v=auTEWanRTfM
www.youtube.com/watch?v=auTEWanRTfM
We can thank our "leadership" -- or lack thereof -- who have been in power for the past 30 years. They dropped the ball with the development of alternative energy research. They idiotically placed all of their faith in the Middle Eastern countries to continue to feed our addiction with cheap oil, even though those people hate us with a passion, for a myriad of reasons.
I personally couldn't care less what happens. I have chosen to not have children, since I would not want them to suffer in the future because of my generation's selfishness. Unfortunately, people didn't adopt the 7-generation rule of my people, the Native Americans. They strove to leave the land in the same shape that they left it, for the enjoyment of the 7th generation down
http://www.sciam.com/article.cfm?id=hydrogen-house&sc=WR_20080624
What the “fossil” companies want is to keep us over an oil barrel. Let’s turn these companies into fossils.
Theories of global cooling start from the late 1950's and continue into the early 1970's. Studies in the Milankovitch Effect (which allows some pre-historic prediction of ice ages on account of variations in the Earth's orbit and orbital inclination) put forth a theory that Earth would probably resume ice age conditions over the next few hundred years or so. Obviously, with anthropogenic emissions of carbon dioxide, this will never happen now - otherwise global cooling might still be a distant threat. Perhaps, this might be the only benefit of global warming...
Evaluating a scientific theory by trying to guess the motivations and biases of the proponents and opponents is pretty useless. Every player can be portrayed as somehow compromised. That's why real science isn't done that way.
How, exactly does one "listen to science"? I've read hundreds of articles on the subject over the years, and the striking change recently is the incredible politicization of what was once a scientific discussion.
The fact that GW proponents have to rely on WHO believes their theory in order to "prove" it, should lead thinking people to be skeptical.
An honest assesment and admission by GW proponents of the limitations of our understanding of nature would go a long way towards convincing skeptics that a scientific process of learning is underway, rather than merely a political process.
If there is one lasting crime BushCo and his ilk have done to the US, it is creating the notion that anyone can evaluate scientific research and draw conclusions - without credentials, peer-review, or regard for the positions of the world's leading scientific bodies. Amazing. Scary.
To split a fat hair, the big crime isn't that BushCo has unduly encouraged lay people to pass judgement on science, it's that they've polticized the actual science itself!
I would suggest that the BushCo WAR ON SCIENCE is the bigger problem than the rejection on faith of good science.
Luckily, there are a few Dr. Hansen's out there. Oh that there were more.
If we think of CO2 as a greenhouse gas heating the earth, then a reasonable analogy is turning on a gas burner under a pot of water. The burning gas heats the air quickly, but it takes a while for the water to get hot. We have turned on the heat with CO2 and are continuing to turn up the burner. It will be on for a long time. It takes a long time to heat the land and water of the earth and temperature rise is now locked in. It will rise until it reaches thermal equilibrium. There is nothing crackpot or hysterical about what I have written. It is basic science.
Oh, by the way, we are all in the pot together.
We're the frog paddling
left in water to frolic
Warm, it is, and comfy.
Warmer yet, we daydream.
Warmer and warmer, we have to drowse.
Getting hot, we start to worry
Hotter yet, it really hurts now!
Boiling it is, cooking us all.
ribit