National Geographic News
Panoramic view of the Mauna Loa Observatory, Hilo, Hawaii.

Two teams of scientists at the Mauna Loa Observatory in Hawaii have been measuring carbon dioxide concentration there for decades, and have watched the level inch toward a new milestone.

Photograph by Jonathan Kingston, National Geographic

Robert Kunzig

National Geographic News

Published May 9, 2013

An instrument near the summit of Mauna Loa in Hawaii has recorded a long-awaited climate milestone: the amount of carbon dioxide in the atmosphere there has exceeded 400 parts per million (ppm) for the first time in 55 years of measurement—and probably more than 3 million years of Earth history.

The last time the concentration of Earth's main greenhouse gas reached this mark, horses and camels lived in the high Arctic. Seas were at least 30 feet higher—at a level that today would inundate major cities around the world.

The planet was about 2 to 3 degrees Celsius (3.6 to 5.4 degrees Fahrenheit) warmer. But the Earth then was in the final stage of a prolonged greenhouse epoch, and CO2 concentrations were on their way down. This time, 400 ppm is a milepost on a far more rapid uphill climb toward an uncertain climate future.

Two independent teams of scientists measure CO2 on Mauna Loa: one from the U.S. National Oceanic and Atmospheric Administration (NOAA), the other from the Scripps Institution of Oceanography. The NOAA team posted word on its web site this morning before dawn Hawaii time: The daily average for May 9 was 400.03 ppm. The Scripps team later confirmed the milestone had been crossed.

The Scripps team is led by Ralph Keeling, son of the late Charles David Keeling, who started the Mauna Loa measurements in 1958. Since then the "Keeling curve," showing the steady climb in CO2 levels caused primarily by burning fossil fuels, has become an icon of climate change.

When the elder Keeling started at Mauna Loa, the CO2 level was at 315 ppm. When he died in June 2005, it was at 382. Why did he keep at it for 47 years, fighting off periodic efforts to cut his funding? His father, he once wrote, had passed onto him a "faith that the world could be made better by devotion to just causes." Now his son and the NOAA team have taken over a measurement that captures, more than any other single number, the extent to which we are changing the world—for better or worse.

Setting the Record Straight

Since late April that number had been hovering above 399 ppm. The Scripps lab opened the vigil to the public by sending out daily tweets (under the handle @Keeling_curve) almost as soon as the data could be downloaded from Mauna Loa, at 5 a.m. Hawaii time. NOAA took to updating its website daily. The two labs' measurements typically agree within .2 ppm. Both measure the amount of CO2 in an air sample by measuring how much infrared radiation it absorbs—the same process by which CO2 in the atmosphere traps heat and warms the whole planet.

 

Scripps chart shows carbon dioxide level hovering at 400 ppm
A chart from Scripps shows the carbon dioxide level hovering near 400 ppm in the first week of May.

Scripps Institution of Oceanography, UC San Diego

 

The measurement NOAA reported for Thursday, May 9, 400.03 ppm, was for a single day. Each data point on the Keeling curve, however, is actually an average of all the measurements made at Mauna Loa over an entire month. The CO2 concentration at Mauna Loa is unlikely to surpass 400 ppm for the whole month of May.

It certainly won't exceed 400 for all of 2013. CO2 peaks in May every year. By June the level will begin falling, as spring kicks into high gear in the Northern Hemisphere, where most of the planet's land is concentrated, and plants draw CO2 out of the atmosphere to fuel their new growth. By November, the CO2 level will be 5 or 6 ppm lower than it is now.

Then the curve will turn upward again: In the winter, plants stop making new carbohydrates but continue to burn the old, respiring CO2 back into the atmosphere.

This seasonal sawtooth—think of it as the breath of northern forests—is the natural part of the Keeling curve. The man-made part is its steady upward climb from one year to the next. Both were discovered at Mauna Loa.

Dave Keeling, as he was known, chose the Hawaiian mountain for his measurements because, at over 11,000 feet and in the middle of the Pacific, it is far from forests or smokestacks that might put a local bias on the data. But even Mauna Loa is not perfectly representative of the whole planet.

NOAA also monitors CO2 at a global network of stations, and the global average consistently lags the Mauna Loa number by a few parts per million—for a simple reason.

"Mauna Loa is higher because most of the fossil fuel CO2 is emitted in the Northern Hemisphere," says NOAA scientist Pieter Tans. It takes about a year, he says, for northern pollution to spread through the Southern Hemisphere.

On the other hand, Mauna Loa lags the Arctic, where CO2 levels are higher. A year ago, NOAA reported that the average of its Arctic measurements had exceeded 400 ppm for the entire month of May, not just for a single day.

The rest of the planet will catch up soon enough. By 2015 or 2016, the whole atmosphere will be averaging 400 ppm for the whole year. What difference will that make?

Back to the Pliocene?

In a way, 400 ppm is an arbitrary milestone, like a .400 batting average in baseball. But the fact that no one has batted .400 since Ted Williams in 1941 still says something important about baseball. The same goes for CO2 in Earth's atmosphere.

Policymakers worldwide have been stymied in their effort to reach a global agreement on reducing fossil fuel emissions. Many scientists argue that the CO2 concentration must be stabilized at 450 ppm to avoid the worst impacts of climate change. Some activists argue for a more ambitious goal of 350 ppm. NOAA has not recorded an average monthly CO2 reading below 350 ppm at Mauna Loa since October 1988.  (See related story: "Obama Pledges U.S. Action on Climate Change, With or Without Congress.")

The last time the concentration of CO2 was as high as 400 ppm was probably in the Pliocene Epoch, between 2.6 and 5.3 million years ago. Until the 20th century, it certainly hadn't exceeded 300 ppm, let alone 400 ppm, for at least 800,000 years. That's how far back scientists have been able to measure CO2 directly in bubbles of ancient air trapped in Antarctic ice cores.

But tens of millions of years ago, CO2 must have been much higher than it is now—there's no other way to explain how warm the Earth was then. In the Eocene, some 50 million years ago, there were alligators and tapirs on Ellesmere Island, which lies off northern Greenland in the Canadian Arctic. They were living in swampy forests like those in the southeastern United States today. CO2 may have been anywhere from two to ten times higher in the Eocene than it is today. (See related: "Hothouse Earth.")

 

Scripps chart shows carbon dioxide level hovering at 400 ppm
Carbon dioxide levels can be seen climbing steadily in Scripps data from the last 55 years.

Scripps Institution of Oceanography, UC San Diego

 

Over the next 45 million years, most of it was converted to marine limestone, as CO2-laden rains dissolved the ingredients of limestone out of rocks on land and washed them down rivers to the sea. CO2-belching volcanoes failed to keep pace, so the atmospheric level of the gas slowly declined. Some time during the Pliocene, it probably crossed the 400 ppm mark, as it's doing now-but back then it was on its way down. As a result, at the end of the Pliocene, it became cold enough for continental ice sheets to start forming in the northern hemisphere. The Pliocene, says geologist Maureen Raymo of Columbia University's Lamont-Doherty Earth Observatory, "was the last gasp of warmth before the slow slide into the Ice Ages."

What was Earth like then? In Africa, grasslands were replacing forests and our ancestors were climbing down from the trees. (See related: "The Evolutionary Road.") On Ellesmere, there were no longer alligators and cypress trees, but there were beavers and larch trees and horses and giant camels—and not much ice. The planet was three to four degrees Celsius warmer than it was in the 19th century, before man-made global warming began.

If anything, those numbers understate how different the Pliocene climate was. The tropical sea surface was about as warm as it is now, says Alexey Fedorov of Yale University, but the temperature gradient between the tropics and the poles—which drives the jet streams in the mid-latitudes—was much smaller. The east-west gradient across the Pacific Ocean—which drives the El Niño-La Niña oscillation—was almost nonexistent. In effect, the ocean was locked in a permanent El Niño. Global weather patterns would have been completely different in the Pliocene.

And yet the two main drivers of climate—the level of CO2, and the parameters of Earth's orbit, which determine how much sunlight falls where and at what season—were essentially the same as today. Fedorov calls it the Pliocene Paradox.

Climate scientists are just beginning to crack it, he says. Maybe clouds outside the tropics were darker in the Pliocene, such that they bounced less sunlight back to space. Maybe the warm ocean was stirred by a lot more hurricanes.

Hanging over this academic research is a very nonacademic issue: Could our climate be capable of flipping to a completely different state? "That's the big question—whether CO2 can move us to the Pliocene," says Fedorov.

Rising Seas

Beavers and camels on Ellesmere Island, instead of glaciers, might not be so bad.  But there was a lot less ice in general in the Pliocene. That means there was a lot more water in the ocean, which means sea level was a lot higher—how high exactly, no one knows.

"The estimates have been all over the map," Raymo says. They've ranged from 10 meters (33 feet) to 40 meters (131 feet) higher than today. But even the conservative estimate, were it to recur today, would mean flooding land inhabited by a quarter of the U.S. population.

Raised Pliocene shorelines have been identified all over the world. One is the Orangeburg Scarp, a wave-cut terrace that parallels the Atlantic coast of the U.S. from Florida to Virginia. Typically it lies more than a hundred miles inland. In the Pliocene, the Gulf Stream flowed past that terrace, over what is now the coastal plain.

The question is: How much has the sea receded since then, and how much has the land risen? Raymo has been asking that question on Pliocene shores in the U.S., Africa, Antarctica.

Land can rise, she explains, because it is was once depressed by massive ice sheets and is now rebounding. It can also rise because the underlying mantle is a hot, viscous fluid that pushes it up—by different amounts in different places. In Virginia the Orangeburg Scarp rises around 70 meters (220 feet) but in Florida only 30 meters (100 feet) above the current sea level. Yet in the Pliocene it was right at sea level in both places. What was that sea level?

Raymo's best guess at the moment, to be confirmed by further fieldwork and modeling, is that the last time Earth had 400 ppm of CO2 in its atmosphere, sea level was somewhere between 10 meters (33 feet) and 20 meters (66 feet) higher than today. To raise sea level 10 meters today would require melting most of the ice in Greenland and West Antarctica. To raise it 20 meters would require melting both those ice sheets entirely and some of the giant East Antarctic ice sheet too.

Ice-Age Clues

Could that happen at 400 ppm? Evidence from the past half million years suggests it could, given enough time.

Since the Pliocene, glacial periods, during which ice sheets advanced over northern continents, have alternated with interglacial periods like the one we're in today. The timing has been set by orbital variations, but CO2 has amplified their effect. For the past 800,000 years at least, its atmospheric concentration has marched up and down in step with the ice, but in the opposite direction.

In the last interglacial period, around 120,000 years ago, sea level was as much as 8 meters (26 feet) higher than today, Raymo says. In an earlier interglacial known as Stage 11, around 400,000 years ago, "the evidence is very strong that sea level was at least 9 meters higher than today. The ice sheets didn't stick around."

In Stage 11, the sunlight distribution was a little less favorable to ice sheets than it is now. CO2 peaked then at 290 ppm.

"What everything is telling you is that the system is very sensitive," says Raymo. "The threshold for losing the Greenland and West Antarctic ice sheets is very close to where we are now. Everything in the geologic record says we're very close. You don't need a lot of CO2—you just need a little bit of warming, and it doesn't matter how you get it."

It took between a thousand and a few thousand years, at the end of Stage 11, to melt all or most of the Greenland and West Antarctic ice sheets. The whole interglacial lasted 30,000 years, nearly three times as long as ours has lasted so far. So the warming had a long time to build up. That's the good news.

But at 400 ppm, CO2 is much higher now, and it's still climbing fast. And even if we could stop that rise tomorrow, the planet's temperature would still climb for centuries.

"For me personally that's the scary thing," says Raymo. "We really don't know what we've already committed ourselves to."

Editor's Note: An earlier version of the story was unclear on when the 400 ppm mark was surpassed. NOAA reported today that the mark had been crossed on Thursday, May 10. Scripps originally reported variable data for the day, then confirmed the milestone had been crossed.

This story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge.

33 comments
Paul Benner
Paul Benner

The last time the concentration of Earth's main greenhouse gas reached this mark, horses and camels lived in the high Arctic. Seas were at least 30 feet higher—at a level that today would inundate major cities around the world.

Elrod Cabana
Elrod Cabana

Global warming caused by humans is a theory, rising co2 ppm is likely to be factual. In science when you have a theory you publish your findings INCLUDING your data and notes. Then you challenge any and all to find fault in your conclusion. You welcome others to show other possible conclusions. Never has a theory been considered so strong it is beyond question. Theories become more likely when many scientist can replicate the findings of the conclusion. Theories move from theory to fact when pretty much any scientist can take your data and conclude the exact same result. Take a hydrogen bomb, it was theory until scientist made one and tested it, then Russia and others were able to do the same. Thus theory became proven. Man caused global warming is so far from being an undisputed fact is laughable. My eyes roll when I hear a real scientist claim co2 is the direct and primary cause of global warming. 400 ppm, few people even know what this means, it is 4 tenths of ONE percent. Co2 has increased from 3 tenths of one percent to 4 tenths of one percent. Math wise one would have to be able to pass the red face test and look all in the eye and with a straight face declare the warming of the earth is directly caused by a trace gas that has increased ONE TENTH OF ONE PERCENT  I mean the average global temp has been rising for a few thousand years. The early ocean explorers documented Hudson Bay as being almost completely ice blocked even in the summer months in the 13th century.

Tiziana Fraresso
Tiziana Fraresso

Share letter to environment minister Spain, Miguel Arias Cañete from Environmental Education Workshop for youth non-formal, in Cordoba Argentina and a call for action on Climate Change problem that endangers the future of the youth.
Best Regards and thak you
Susana t.
_______________________________
Sr. Cónsul de España en Córdoba
S_______//______D
 
De nuestra mayor consideración
 
El Ministro de Ambiente de  España, Sr. Miguel Arias Cañete en la Expo Carbon 2013 pidió: "Hay que actuar, actuar ya"  referido al Cambio Climático (1)
Y nos dejó con esta frase  preocupados por que pensábamos que si estamos en la COP19 es por que se viene actuando... ¿o será que los jovenes confundimos hablar, reunirnos y escribir documentos con siglas difíciles casi encriptados, evaluar mediciones, y lograr consensos, con "actuar" y por esto el Cambio Climático no se frenó sino que sigue avanzando y estamos en 400 ppmm de gas de efecto invernadero más alto desde el Plioceno, cuando los niveles del mar eran más altos y la Tierra era más cálida.? (2)
Respetuosamente, si el Sr. Ministro esta preocupado cuanto mas estamos nosotros que somos simples jóvenes de un precario Taller y que miramos sin entender la cantidad de Reuniones de Alto Nivel que se han sucedido mientras observamos el nivel de descongelamiento del Ártico, donde se mide el problema a simple vista de un profano en la materia.
También nos preguntamos si el Sr.Ministro en la próxima Cumbre de Cambio Climático para lograr esa "Acción" que estima debe suceder "ya",podría proponer que a mas de los políticos, los diplomáticos, los científicos y los ambientalistas se incorpore a un filósofo que explique sobre el método de la Ética que desarrollaron los griegos para regular las acciones humanas...
Agradeciendo su atención de transmitir la inquietud de los jóvenes cordobeses sobre su futuro al Sr. Ministro, saludo a usted con especial consideración.
Susana Tibaldi
Para Taller de Educación Ambiental No Formal Mayu Sumaj Cordoba.
(1) http://news.nationalgeographic.com/news/energy/2013/05/130510-earth-co2-milestone-400-ppm/
(2) http://www.magrama.gob.es/es/prensa/noticias/-miguel-arias-cañete-“hacer-frente-al-cambio-climático-exige-actuar,-y-actuar-ya”/tcm7-283315-16

James Scott
James Scott

Maybe I missed it, but how are you accounting for the fact that you are taking the readings in an active volcano chain? If I rember right back in 2007 there was a report that put out that volcanos put out 300 tons of co2 a year into the atmosphere as compared to Humans who where sitting at about 25 tons.   This to me is an indication of a larger volcanic activity, Which is truely problematic that brings up a whole new nest of concerns that we should be looking into.

Paul Atreides
Paul Atreides

Sponsored by Shell?  The oil company?  Paid for this article?  No conflict of interest there! 

Gerard Mathias
Gerard Mathias

WORLD WIDE BIRTH CONTROL AWARENESS IS THE ONLY SOLUTION. YOU CAN'T HAVE 9 BILLION PEOPLE ON THIS PLANET AND NOT HAVE CATASTROPHIC EFFECTS ON THE ENVIRONMENT. OUR SEAS ARE EMPTY, THE RAIN FORESTS ARE DISAPPEARING, CO2 LEVELS RISING, ETC. OVER-POPULATION IS THE REASON. WHY IS OVER-POPULATION AND BIRTH CONTROL NOT THE NUMBER ONE TOPIC TODAY?

Bob Burnitt
Bob Burnitt

The problem is and will always be, even though NOBODY will face it, is there are too many people on Earth.  Thirty years ago, we had 2 billion people.  In thirty years the population has gone to 7.3 billion.  That is unsustainable and a DISASTER nobody will face or even TALK about.  You cannot have Infinite Growth in a Finite World.  Thomas Malthus was RIGHT and that is where we are headed Malthusian Misery.  Most of the world is already THERE.  Bob Burnitt

Enon Raored
Enon Raored

To quote the story "Many scientists argue that the CO2 concentration must be stabilized at 450 ppm.."

A misprint?

 Hansen and Sato (2011)using paleoclimate data rather than models of recent and expectedclimate changewarn that “goals of limiting human made warming to 2°C and CO2to 450ppmare prescriptions for disaster”.

450ppm will result in an average global temperature exceeding that of the Eemian, producing decadal doubling of the rate polar ice loss, resulting in sea level rise of up to 5m by the end of this century.  That prognosis is one which can not be ignored.  Atmospheric CO2 concentration of 450 ppm may be an icon to which politicians and corporations cling but it is wrong and dangerously so. 

So which 'scientists' were the article referring to? It never said.

Alec Sevins
Alec Sevins

Unfortunately, the byline for this story - "Greenhouse gas highest since the Pliocene, when sea levels were higher and the Earth was warmer" - is a perfect setup for right-wing cherry picking and context burying.

They'll dwell on that one line as a talking point and ignore the entire content of the article. "See, if CO2 was that high back then, why isn't the Earth warmer with higher sea levels now?!" They will ignore many contextual elements of that ancient time period, and the fact that we've never had this level of warming with modern infrastructure at stake.

But that's what right-wingers are all about; ignoring context and cherry-picking data to push their money-centric, anthropocentric agenda.

Bob Elliott
Bob Elliott

The last time the concentration of Earth's main greenhouse gas reached this mark, horses and camels lived in the high Arctic. Seas were at least 30 feet higher—at a level that today would inundate major cities around the world. And even if we could stop that rise tomorrow, the planet's temperature would still climb for centuries.

Asok Smith
Asok Smith

WOW! This is an amazing article! It desperately wanted to say that the "record" CO2 was making things warmer. But it couldn't. Know why? Because the Earth is NOT getting warmer! Hasn't for 16 years. I guess they didn't want to mention that little factoid in the same article that was pimping an  "all time high" CO2 number. People might get the wrong impression. Instead they totally dance around the issue by repeated emphasizing it was supposedly hotter a long time ago. As it is, I guess NatGeo must simply be hoping people have been so brainwashed and are so unable to actually think  for themselves any longer that they'll will mentally fill in the deliberate blanks with "higher CO2= Global Warming".

Asok Smith
Asok Smith

WOW! This is an amazing article! It desperately wanted to say that the "record" CO2 was making things warmer. But it couldn't. Know why? Because the Earth is NOT getting warmer! Hasn't for 16 years. I guess they didn't want to mention that little factoid in the same article that was pimping an  "all time high" CO2 number. People might get the wrong impression. Instead they totally dance around the issue by repeated emphasizing it was supposedly hotter a long time ago. As it is, I guess NatGeo must simply be hoping people have been so brainwashed and are so unable to actually think  for themselves any longer that they'll will mentally fill in the deliberate blanks with "higher CO2= Global Warming".

michael freitas
michael freitas

Incredible that this news is nowhere to be seen on major news sites.  I did see a segment on All In with Chris Hayes yesterday. Thank you National Geographic for covering our undoing. Someday humans will look back on this and say WTF dummies.

Sid Abma
Sid Abma

The US EIA states that in 2012 commercial buildings and industry and the power plants consumed approx. 17.5 trillion cu.ft. of natural gas.                                      How much of this was wasted, blown up chimneys across the country as HOT exhaust into the atmosphere?  At what temperatures?

The US DOE states that for every 1 million Btu's of energy recovered from those natural gas waste exhaust gases, and this recovered heat energy is utilized back in the building or atmosphere, 118 lbs of CO2 will NOT be put into the atmosphere.

The technology of Condensing Flue Gas Heat Recovery is designed to recover most of that heat energy from those waste exhaust gases, making this recovered heat energy available for use. Being vented into the atmosphere will be COOL exhaust.

Last year the World Energy Congress stated that natural gas was the worlds most important energy source from now till at least 2050. If the world learns to utilize this energy efficiently, how much CO2 would NOT be vented into the atmosphere? How much of a difference will this make for the future?

James Greyson
James Greyson

"Policymakers worldwide have been stymied in their effort to reach a global agreement on reducing fossil fuel emissions"

I'd say that policymakers have been stymied in reaching a global agreement because it only aimed to reduce emissions. This small ambition generates small thinking and small policy proposals that do absolutely nothing to reconfigure human impacts to cut CO2 concentrations.

Policies to cut the atmospheric stockpiles are not difficult to determine (NATO published some of my suggestions) and not even economically prohibitive. We just need public policy debate calibrated to the whole problem - not just adjustments to increments of the problem.

Elias Fernandez
Elias Fernandez

@Elrod Cabana Fundamental correction: A hypothesis requires the proper experimentation and/or systematization of evidence. Once those basic requirements are met, the object becomes a theory. Therefore a theory comprises that which was proven, -its formulae and explanation- as a body of knowledge to explain; describe; reproduce the phenomena and predict the behavior of the same under different parameters.

Being so, man-made global warming must be discussed (in this context) as whether it is a hypothesis or a theory. 

Paul Atreides
Paul Atreides

What are you talking about?  Not even close.  You must have gotten your information from Fox News or ExxonMobil.  "Human activities emit roughly 135 times as much climate-warming carbon dioxide as volcanoes each year." http://news.discovery.com/earth/weather-extreme-events/volcanoes-co2-people-emissions-climate-110627.htm

"Thus, not only does volcanic CO2 not dwarf that of human activity, it actually comprises less than 1 percent of that value." http://hvo.wr.usgs.gov/volcanowatch/archive/2007/07_02_15.html

Paul Atreides
Paul Atreides

I'm guessing that the byline had to be approved by Shell Oil, the sponsor of the article. 

But, aren't money-centric and anthropocentric mutually exclusive?

Paul Atreides
Paul Atreides

^^^ The words of one definitely not brainwashed by Fox News, Sean Hannity, Rush Limbaugh or ExxonMobil.

Alec Sevins
Alec Sevins

@Asok Smith There's that old "no warming since the 1998 El Nino spike that mindless right-wingers take out of context" thing again.

Tell a right-winger that 2012, 2010 and 2005 have been the warmest years on record (and that 2013 may well break more records) and the right-winger will just look at its list of Rush Limbaugh talking points and babble "no warming in 16 years!"


Anon .
Anon .

@Asok SmithIn the Guardian Newspaper on 12th December 2009, a science correspondent, Ben Goldacre asked why “roughly half of the people in this country do not believe in man-made climate change, when the overwhelming majority of scientists do?” He suggested the following explanation: 

• We are predisposed to undervalue adverse outcomes which are a long way off, especially if we might be old or dead soon; 

• We are predisposed to find cracks in evidence that suggests we should do something we don’t want to do; 

• Climate science is difficult; 

Also, the Earth was formed 4.5 billion years ago, so I hardly see how 16 years is relevant in the grand scheme of things.

Emile Nossin
Emile Nossin

@Asok Smith , the science contradicts your statement. It has warmed a lot, here you can see (and explained) what the science says (you can click on the intermediate tab for more details): http://sks.to/16years

Emile Nossin
Emile Nossin

@Sid Abma Switching partly to gas will make matters worse, because it still produces CO2 and the false sense of security it gives people (slightly cleaner is like slightly less deadly) it will delay investment into true durable energy. You might also like to check the movie Gasland to learn more about fracking: http://youtu.be/kJyZhZcQOLI

John Strohl
John Strohl

@Sid Abma But what we NEED to do is just shift our focus to renewables and stopped the use of carbon based fuels. Then we'd know how much CO2 was going into the atmosphere from the use of fossil fuels - NONE! That's where we need to be. The damage is already done. There is a 40 year lag on cause and effect. If we stopped all carbon emissions today, we wouldn't see the effect on global warming until we'd gone another 40 years down the timeline. There is no better example of the meaning of such terms as tipping point and over-shoot.

Paul Atreides
Paul Atreides

•  The main stream media - which is owned by a half dozen multinational corporations, and which sells advertising to multibillion dollar, multinational oil companies - continually repeats ExxonMobil's propaganda that global warming is a liberal conspiracy made up to mislead gullible SUV drivers. 

Paul Atreides
Paul Atreides

In one hour, the Earth is bombarded by more solar energy than the entire human consumption of energy in a year.  But, solar energy is a clean, free and unlimited natural resource.  So, that idea will be fought, on every front, in every conceivable and inconceivable manner, by those who sell oil, perhaps until it's too late. 

Having said that, I will leave you with the possibility that it is more likely that the toxicity of oil and oil derived plastics and petro chemicals will impair animal fertility to the point of extinction before global warming has a significant affect on animal life sustainability.

Just a thought.

Michael Bradley
Michael Bradley

@Paul Atreides You're right, hydrogen and solar are "clean", any fossil fuel is not...but until companies reduce the cost or increase the efficiency of solar panel, wind power, hydrogen power, etc., fossil fuels will remain a major power source....with electric cars, we can rely more on hydroelectric and less on fossil fuel, until the technological breakthroughs occur.....which is why I said "within 50 years......."

Paul Atreides
Paul Atreides

First, 50 years may be too late.  Second, leaked natural gas itself (as opposed to the co2 from burnt natural gas), is lighter than air and is a more potent greenhouse gas than co2 by 10 orders of magnitude.  Finally, I would much rather U.S.policy promote development of solar and hydrogen power.

Michael Bradley
Michael Bradley

@Paul Atreides Hopefully - within the next 50 years

1)  First, the US will be self-sustaining natural gas producer, being an exporter, not dependent on foreign oil...

2)  Cars will be Hydrogen powered

3)  hydrogen power will produce most electricity throughout the world.....(or combined with Hydroelectric power).....

4)  Unsafe nuclear power will no longer be needed.

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