Mar 08 2011

Climate Emergency: Time to Slam on the Brakes

I wrote this post for Skeptical Science as a basic rebuttal of the argument “It’s not urgent”.

Global warming is an increasingly urgent problem. The urgency isn’t obvious because a large amount of warming is being delayed. But some of the latest research says if we want to keep the Earth’s climate within the range humans have experienced, we must leave nearly all the remaining fossil fuels in the ground. If we do not act now we could push the climate beyond tipping points, where the situation spirals out of our control. How do we know this? And what should we do about it? Read on.

James Hansen, NASA’s top climatologist and one of the first to warn greenhouse warming had been detected, set out to define dangerous human interference with climate. In 2008, his team came to the startling conclusion that the current level of atmospheric carbon dioxide (CO2) is already in the danger zone.

Since the Industrial Revolution, atmospheric CO2 has increased from 280 to 390 parts per million (ppm). Don’t be fooled by the small number – 390 ppm is higher than CO2 has been in millions of years. CO2 is rising by 2 ppm per year as we continue to burn fossil fuels. To stabilise the Earth’s climate, we must reduce CO2 to the relatively safe level of 350 ppm. And we must hurry, because the task will soon be an impossible one.

The 350 target is based not on climate modeling, but on past climate change (“paleoclimate”). Hansen looked at the highly accurate ice core record of the last few hundred thousand years, sediment core data going back 65 million years, and the changes currently unfolding. He discovered that, in the long term, climate is twice as sensitive in the real world as it is in the models used by the IPCC.

The key question in climate modeling is how much global warming you get from doubling CO2, once all climate feedbacks are taken into account. A feedback is something that amplifies or cancels out the initial effect (eg. interest is a feedback on a loan). The models include “fast feedbacks” like water vapor, clouds, and sea ice, but exclude longer-term “slow feedbacks” like melting ice sheets (an icy surface reflects more heat than a dark surface).

Both models and paleoclimate studies agree the warming after fast feedbacks is around 3°C per doubling of CO2. Slow feedbacks have received far less attention. Paleoclimate is the only available tool to estimate them. To cut a long story short, Hansen found the slow ice sheet feedback doubles the warming predicted by climate models (ie. 6°C per CO2 doubling).

Long-Term Climate Sensitivity

The global climate has warmed only 0.7°C, but has not yet fully responded to our past emissions. We know this because the Earth is still gaining more heat than it is losing. There is further warming in the pipeline, and Hansen’s results imply there’s a lot more than in the models. If CO2 remains at 390 ppm long enough for the ice sheet feedback to kick in, the delayed warming would eventually reach 2°C. That would result in an Earth unlike the one on which humans evolved and a sea level rise of not one metre, not two metres, but 25 metres. Imagine waves crashing over an eight-storey building.

It’s hard to dispute this would be “dangerous” climate change. But how quickly could it happen? In the past, ice sheets took millennia to respond, though once they got moving sea level rose several metres per century. But maybe ice sheets can melt faster if CO2 rises faster, as it is now doing. The IPCC predicted they would grow by 2100, but instead they are starting to shrink “100 years ahead of schedule”. Once an ice sheet begins to collapse there is no way to stop it sliding into the ocean. We would suffer centuries of encroaching shorelines. The climate change we started would proceed out of our control.

If ice sheets can melt significantly this century, then Hansen’s long-term warming has near-term policy implications. The tragedy we have set in motion can still be prevented, if we get the Earth to stop accumulating heat before slow feedbacks can kick in. To do so we must target the greatest, fastest-growing, and longest-lived climate driver: CO2.

Under business as usual, we are heading for up to 1,000 ppm by 2100, or nearly two doublings (and that’s not including possible carbon feedbacks). This would surely be an unimaginable catastrophe on any timescale. Even the mitigation scenarios governments are quarreling over are based on IPCC assessments now several years out of date. The lowest CO2 target being considered is 450 ppm, which Hansen concluded would eventually melt all ice on the planet, raising sea level by 75 metres. The Earth has not been ice-free since around the time our distant ancestors split off from monkeys.

Instead of stepping on or easing off the accelerator, we need to be slamming on the brakes. We must not only slow the rise of CO2 in the atmosphere, but reverse it. We must reduce CO2 from 390 to 350 ppm as soon as possible. That should stop the planet’s accumulation of heat. Stabilizing the CO2 level will require rapidly reducing CO2 emissions until nature can absorb carbon faster than we emit it – in practical terms, cutting emissions to near zero.

The only realistic way of getting back to 350 ppm is leaving most of the remaining fossil fuels in the ground. We must:

1) phase out coal by 2030. It is not enough to slow down coal-burning by converting it to liquid fuels, because CO2 stays in the atmosphere for a very long time. The fundamental problem is with the coal being burned at all.

2) not burn tar sands or oil shale. Their reserves are virtually untapped but thought to contain even more carbon than coal. Canada cannot keep burning them.

3) not burn the last drops of oil and gas if their reserves are on the high side. If it turns out we have already used about half, then we can safely burn the rest.

4) turn deforestation into reforestation. We’d still be left with the gargantuan task of removing CO2 from the atmosphere. Nature can absorb some carbon, but it has limits.

CO2 Emissions and Atmospheric Concentration with Coal Phaseout by 2030

It won’t be easy, but with these actions CO2 could peak around 400 ppm as early as 2025 and return to 350 ppm by century’s end. I believe we can achieve this; it’s primarily a question of political will. But our window of opportunity is rapidly slamming shut. Even one more decade of business as usual, and CO2 can be expected to remain in the danger zone for a very long time.

I should point out estimating a CO2 target from paleoclimate is fraught with uncertainties. I’ve had to simplify for this short article. I explain in more detail on Skeptical Science, or you can read Hansen’s paper free here. If there is one lesson recent climate research should teach us, it is that it’s a mistake to call uncertainty our friend. Arguably the most important aspect Hansen ignores, carbon feedbacks, is likely to make things even worse. There is more than enough reason to heed Hansen’s warning.

Right now we stand at an intersection. What we do in this decade is crucial. If we choose one path, by the end of the decade the world could be well on its way to phasing out coal. If we choose the other, we face an uncertain future in which the only certainty is a continually shifting climate. I’ll leave the final word to Hansen et al, whose concluding statements were pretty strongly worded coming from a dense, technical, peer-reviewed paper:

Present policies, with continued construction of coal-fired power plants without CO2 capture, suggest that decision-makers do not appreciate the gravity of the situation. We must begin to move now toward the era beyond fossil fuels. […] The most difficult task, phase-out over the next 20-25 years of coal use that does not capture CO2, is Herculean, yet feasible when compared with the efforts that went into World War II. The stakes, for all life on the planet, surpass those of any previous crisis. The greatest danger is continued ignorance and denial, which could make tragic consequences unavoidable.


  1. criticalblogger

    (note – documented evidence for any claims below can be found in my blog)

    The CO2 / AGW so called ‘science’ and even the so called ‘consensus’ is falling apart. Even IPCC members are now distancing themselves from their own proclamations and admitting the organization was political from the beginning. Even Royal Society scientists have demanded their society distance themselves from the theories of AGW.

    Meanwhile Al Gore is being sued for fraud (over his cap and trade schemes which, by the way, have had their origins traced back to Enron) by 30,000 scientists including the founder of the weather channel. HIs film was found to be erroneous in at least 9 significant places by a high court judge and we are now on the THIRD rebranding of this phenomena as ‘climate disruption’ after ‘climate change’ and ‘global warming’. Note how each one waters down its meaning to account for the climate’s refusal to do what the fear-mongering said it would.

    Now we have ‘climate disruption’ which basically means ‘weather’.

    One thing which CAN be proven by science without a shadow of a doubt is that there IS a well established, well funded and well documented political agenda behind this movement (Agenda 21) and it IS being pushed onto the public without any proper discussion. The fact that the media refuses to even mention Agenda 21, the Club of Rome and documents like the ‘First Global Revolution’ is highly significant and only serves to reinforce the fact that a political agenda is being implemented. If this agenda is nice and helpful to humanity as a whole then why is it never mentioned?

    The answer of course is that it is an agenda to control and enslave of the general population through a so called ‘war on carbon’ which basically translates as a war on private wealth, private land ownership, individual rights and individual freedoms. What we have is a political agenda dreamt up decades ago by globalist criminals, fraudsters and the political elite which in their OWN DOCUMENTS says it will use the IDEA of a threat of global warming to manipulate policies and the public in order to usher in a new age of global governance and environmentally justified lowering of the living standards for the masses – and with a handy new global taxation scheme to help pay for the administration cost of setting up this whole new system.

    Then you have dodgy science and even more dodgy preachers caught lying and cheating about the facts. Again this is proven and documented.

    We also see attempts being made to label dissenters / skeptics are ‘deniers’ with even calls to imprison and murder them being made on national news programs and in the press!

    What we are seeing is a new age church and religion (based this time on hijacking science rather than hijacking spirituality) being set up to control the masses through fear and through taxation and through control of information…. in other words history repeating, the same old tactics being used by the same old bunch of elite criminals and the same old gullible public falling for it all over again!

    Yet despite all of this the public is now increasingly rejecting AGW as are many investors and policy makers (meaning the renewables bubble is now collapsing). This is highly significant…. imagine what will happen when ALL of the truth gets out into the public domain?! Total collapse and exposure of AGW and the whole renewables scam. This is already underway with many countries (Spain, Denmark) now abandoning their ‘renewables’ targets as they start to realise it will bankrupt their nation and not even come close to meeting their energy needs.

    I understand this was written before the Japan earthquake but in light of all of this if the world now (inevitably) moves away from nuclear (which can only be a good thing) and if the world is ALSO convinced to abandon (or heavily limit) fossil fuels/ CO2 in the short term (when we need them the most) because of fear mongering over so called ‘global warming’ then we WILL slide into a new medieval period. Period.

    Imagine what effect power shortages will have on the economy which is already about to drop off the cliff into total depression/ hyperinflation etc.

    We could see the west reduced to the status of third world countries again. Look at the US … a military dictator in all but name pursuing aggressive wars which the country can;t afford, while printing money like there’s no tomorrow to pop up an economy which is dying, while people go hungry and homeless, unemployment skyrockets and violence erupts. How is that NOT a pretty good preliminary sketch of a third world country?

    I am all for so called ‘renewables’ on a local/ individual scale (wind turbine in your back yeard etc) but as a **centralized** means of power generation ‘renewables’ DO NOT WORK!!! They require massive subsidy and back up from coal etc. They only create profits for a few energy companies and increased tax/ bills for the rest of us …. they DO NOT PRODUCE significant power.

    Even industry insiders and experts are saying we are headed towards blackouts in the west if we do not steer away from current INSANE energy policies. (check my blog for articles etc etc)

    And all of this fits perfectly with the agenda to cull the population, put the masses in eco cities under total big brother surveillance and with ALL ‘luxuries’ such as water, electricity, travel heavily rationed and controlled by a central authority… in other words the kind of society Hitler could only have dreamt about … yet thanks to ‘green’ propaganda some of us are begging to have this model imposed upon us! The youth are – because they have been brainwashed and have no idea what they are wishing for (apart from a chance to ‘stop the sea level rising and drowning them’). The amount of green propaganda being pumped into the minds of children (in schools etc) today is obscene! (again check my blog…)

    The bottom line and uncomfortable truth is that the entire green movement has been hijacked. Of course, there are massive energy and environmental needs and challenges which need to be addressed and solutions found … but simply following these maniacs and their policies is not the answer – it is suicidal.

    Our leaders as controlled by lobbyists and the global elite banking aristocracy are the most environmentally destructive force on the planet NOT the masses.

    WAKE UP.

    The Atlantic is now full of oil the Pacific is now filling up of radiation, GM contamination everywhere and the destruction of higher yield, more environmentally safe methods of farming (organic) and its replacement with of Big Agra *patented* nutrition less crap instead (in the name of ‘codex alimentarius’ – see my blog etc)…. The problem is the elite globalists, elite bankers, mega corporations and mega contractors etc – the powerful and psychopathically greedy lobbyists! Monsanto, GE, BP, Lockheed Martin blah blah blah….

    This madness has to stop.

    (to learn about Agenda 21 etc please see my blog – there’s just too much info to link here).

  2. Time Traveller

    I think you need to view this.


    The real science is falling into line with the intuitive view – that the sun drives temperature variations. As criticalblogger points out, the green agenda was hijacked by the bankers and the big corporations long ago and it is they who are maintaining the CO2 myth for control and profit.

    The one part of your agenda with which most of us can agree is your call for reforestation but it is probably too late. Sadly, the greens’ strange fixation with banning oil has opened the door for the money men to destroy rain forest and habitat under the guise of creating biofuels to ‘save the planet’. Yeah – right.


  3. Sheree

    I’m glad you mentioned feedbacks in this post as I think that’s probably the most important aspect of climate change that people simply do not understand. Basically if you start of with something seemingly small and insignificant it can trigger a chain of events that amplify the situation.
    For example, an initial increase in carbon dioxide creates slight warming, which in turn causes more evaporation of water (the most influential greenhouse gas) which then warms the climate even more. Similarly, initial warming can trigger ice melting, which lowers the albedo of the surface and causes further warming (ice-albedo feedback).
    Most of the uncertainties surrounding climate change are in relation to how all these feedbacks interrelate to regulate the climate. So far, observations have followed the more extreme side of climate models showing just how complex these feedbacks can be.
    Good post I enjoyed reading it :)

Leave a Reply

%d bloggers like this: