Tipping Points Near
by James Hansen

http://www.worldwatch.org/node/5798

Today, I will testify to Congress about global warming, 20 years
after my June 23, 1988 testimony, which alerted the public that
global warming was under way. 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.

Then: Time to "Stop Waffling"
On June 23, 1988, I testified to a hearing chaired 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 ongoing 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 United States refused to place limits on its
emissions, and developing countries such as China and India rapidly
increased their emissions.

The Coming Storm
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 this
century. Hundreds of millions of people would become refugees. No
stable shoreline would be reestablished in any time frame that
humanity can conceive.

Animal and plant species are already stressed by climate change.
Polar and alpine species will be pushed off the planet, if warming
continues. Other species attempt to migrate, but as some are
extinguished, their interdependencies can cause ecosystem collapse.
Mass extinctions, of more than half the species on the planet, have
occurred several times when the Earth warmed as much as expected if
greenhouse gases continue to increase. Biodiversity recovered, but it
required hundreds of thousands of years.

Getting to 350 ppm
The disturbing conclusion, documented in a paper[1] 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 by about 2 ppm per year. Stunning 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 worldwide, 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 rainforests of the ocean, are home for 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.

Moving Away from Fossil Fuels
Requirements to halt carbon dioxide growth follow from the size of
fossil carbon reservoirs. Coal towers over oil and gas. Phasing out
the use of coal 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 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 the transition to our renewable energy
future. Instead of moving heavily into renewable energies, fossil
fuel companies choose to spread doubt about global warming, just as
tobacco companies discredited the link between smoking and cancer.
Methods are sophisticated, including funding to help shape school
textbook discussions of global warming.

CEOs of fossil energy companies know what they are doing and are
aware of the long-term consequences of continued business as usual.
In my opinion, these CEOs should be tried for high crimes against
humanity and nature.

But the 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 yield continued exorbitant profits for a short-
sighted, self-serving industry, but no alleviation of our addiction
or long-term energy source.

Pricing Carbon Emissions
Moving from fossil fuels to clean energy is challenging, yet it is
also 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 were it 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.
A carbon tax with a 100 percent dividend[2] is needed to wean us off
of our fossil fuel addiction. A tax and dividend allows the
marketplace, not politicians, to make investment decisions.

A 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.

A carbon tax with a 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 U.S. 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.

America's Role
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,
and 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!"

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, in a way 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 fuel industry maintains its stranglehold on Washington via
demagoguery, using China and other developing nations as scapegoats
to rationalize inaction. In fact, the United States produced most of
the excess carbon in the air today, and it is to our advantage as a
nation to move smartly in finding 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.

The United States 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 it churns slowly. Time is short. The
2008 election is critical for the planet. If Americans turn out to
pasture the most brontosaurian congressmen, and if Washington adapts
to address climate change, our children and grandchildren can still
hold great expectations.

Dr. James E. Hansen, a physicist by training, directs the NASA
Goddard Institute for Space Studies, a laboratory of the Goddard
Space Flight Center and a unit of the Columbia University Earth
Institute, but he testifies here as a private citizen.















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