Editorial viewpoints from Climate Central's writers and editors.

400 ppm: A Milestone that Means Everything, and Nothing

By Michael D. Lemonick

I’m not big on taking note of milestones. They’re artificial, and usually meaningless, but people get all worked up about them anyway. I don’t like to stay up late on New Year’s Eve, for example, because Dec. 31 is a purely arbitrary date. Nothing real actually begins the next day, but we all pretend otherwise. I have similar feelings about the first day of spring, the temperature reaching 100° as opposed to 99° and all sorts of other magic-sounding dates and numbers that don’t have any real significance.

But since no law says I have to be consistent, I’m going to take note of a milestone that happened some time in the past couple of months, and which was reported last week by NOAA. For the first time in recorded history, and almost certainly for much longer than that, the atmosphere’s concentration of carbon dioxide, or CO2, has nipped above 400 parts per million in at least one part of the world. Monitoring stations in Alaska, northern Europe, and Asia have all noted readings above that level during this past spring.

In one sense, this isn’t all that important. There’s no meaningful difference between 399 ppm and 400, and the current world average is more like 393. Even in the Arctic, scientists know the CO2 level will drop back below 400 this summer, as trees in the Northern Hemisphere suck carbon dioxide back out of the atmosphere (you can see the annual ups and downs as trees start growing in the spring and go into hibernation in the fall). We won’t get to a world average of 400 for several years yet.

Climate scientists generally agree with all that, but suggest that the 400 ppm milestone is important anyway, for symbolic reasons. “It's just a reminder to everybody that we haven't fixed this and we're still in trouble,” Jim Butler at NOAA’s Earth System Research Lab told the Associated Press.

I don’t know if the reminder will do much good, given the seeming indifference with which policymakers have responded to earlier CO2 milestones. I think reaching 400 parts per million anywhere in the world is crucially important for an entirely different reason: however much CO2  is in the atmosphere today is the minimum level we’re going to have to live with for the indefinite future. Once carbon dioxide is swirling around in the stratosphere above us, it will stay there for hundreds and hundreds of years. It’s as though you gained the most weight in your life, and knew you’d never weigh even a single pound less, ever.

CO2 does eventually get pulled back out of the atmosphere by natural processes, but that happens very slowly. Climate scientists like to compare the atmosphere to a bathtub half-full of water, with a very slow drain and a slowly trickling faucet. If the drain and the trickle are balanced, the water level never changes — just as the trickle of natural CO2 into the atmosphere and the drainage into trees, carbonate rocks and other places have been in balance for at least 2,000 years, and probably more. Atmospheric CO2  hovered at around 270-290 parts per million that whole time, and the climate stayed more or less stable.

Recent monthly mean CO2 measured at Mauna Loa Observatory in Hawaii. Credit: NOAA.

Since the wholesale burning of fossil fuels began with the Industrial Revolution, however, CO2 levels have been climbing. The faucet has been opened wider, but the drain is still very slow. And even if we manage to cut emissions significantly — something that’s not looking likely anytime soon — the faucet will still open wider than it was in pre-industrial times. CO2 levels will continue to climb, just not as fast.

So once we get to 400 (or 425 or 450 or 500 or whatever), that’s where we’ll be for the foreseeable future. The elevated temperatures caused by this crucial heat-trapping gas will be with us indefinitely as well. The world’s glaciers and ice caps will continue to melt — just think of the difference between putting a small block of ice in a hot oven for 10 seconds and putting it in there for an hour. The oceans will continue to warm. As a result of both the melting and warming, sea level will continue to rise. Scientists expect the oceans to be perhaps 3 feet higher by 2100, but it won’t stop then (which means, by the way, that 2100 is another meaningless milestone).

And all of that’s going to be true even if we cut back drastically on emissions. If we don’t, then every new CO2 milestone — 500 ppm, 800, 964, whatever number you choose — will be the new the level of climate-changing pollution the planet will have to deal with at the very minimum from that time onward.

Maybe that’s another reason for me to ignore milestones from now on. They’re either meaningless, or highly depressing. Or, as in this case, both at once.

« Commentary


By Peter Mizla (Vernon Rockville, CT)
on June 5th, 2012

Considering C02 has not been near 400ppm in perhaps 4 million years- or as much as 15 million years its certainly significant. That we are adding now every year over 2ppm to this total is even more depressing. That we are changing the planets climate 50 times faster then anytime in geologic history is also a bummer. That we have a society who is totally clueless is another factor which only can be blamed on special interests who care less about future life on the planet.

That we have become morally bankrupt and ethically absent will end with disastrous results- and it will happen quicker then anyone now can imagine.

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By Jo Hayward-Haines (Ennismore, On. K0L 1T0)
on June 6th, 2012

Though I am fairly well-aware of the fact and effects of climate change, I hadn’t known we were racing fast on a dead-end street as far as the nearly constant accumulation levels of C02 in the atmosphere goes.  Since this is such a devastating situation, what degree of passionately creative response do we need to see? As Ernest Callenbach noted - maybe it was in his book Ecotopia - “Looters are gnawing on the carcass of the collapsing empire.” Unfortunately, the health of the Earth itself with all its amazingly complex ecosystems and forms of life is at risk as well. We are summoned to new ways of responding which reflect our awareness that what we do to the Earth we do to ourselves, as Chief Seattle said over a century ago.  Even more compelling is the dynamism that arises from our sense of awe at being alive on such a beautiful - “Hoeshk” ( Navajo) Earth, in such a wondrously vast and complex universe. Surely we are capable of changing our destructive, self-centred ways.  Let’s begin to examine together how we can do it.  We are the community of the ones who are waking up, wherever we may live..

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By Stan Lippmann (Seattle, WA 98115)
on June 13th, 2012

I attended ICCC7 in Chicago.  Among other things I learned is that the data shown here is a total fraud. On the morning that climategate hit, I called the physicist in charge at Mauna Loa and confronted him the the satellite data, showing several percent variation in CO2 around the world.  I learned that the graph shown here is a fraud based on the phony black box designed by Roger Revelle back in the 1960’s.  As a Ph.D. myself, when the physicist at Mauna Loa could not explain what was in the black box to me himself, it confirmed that AGW is nothing but a genocidal mass murder plot by fake money bankers and Nazi eugenicists going all the way back to Aarhenius back in 1896.  Look at the comments of the deluded fools who refuse to confront the reality that this is the biggest scientifc fraud in history, “Oooh Oooh Oooh, life sucks, people suck, Ooooh, Ooooh, Ooooh.” This is precisely the point of this scam.  They Zionist bankers want to turn us into wimpering crybabies who are unable to reproduce.  Specifically, this psychological warfare plot is targeting the one people on this planet that can bring gangsters like Al Gore to retributive justice.  I have no doubt that everyone who profited from this scam will face adjudication at the new Star Chamber on Reality TV Grand Jury, live from Nuremberg, Pennsylvania. I hope to be Chief Prosecutor.  The American People will collectively decide the fate of all of the fake scientist carbon grifters.

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By David Wadlow (NJ)
on June 16th, 2012

I appreciate this article.  I think it is indeed very important. I also sympathize with the writer for trying to highlight this, and to other members of the human race, all other living things and the planets ecosystems - in advance.  It should be a loud warning shout.  400ppm CO2 is a significant milestone, for all the reasons mentioned.  Committed global warming is now a notch higher - with all that that means. Oh man. And yet this is the only ‘media’ response I have personally so far seen about it.  It is surreal. As far as I can see, the general public is almost entirely disengaged from the topic of climate change. I wonder what Salvador Dali would have made of this.

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