Meinshausen: Why we have to suck CO2 out of atmosphere

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Climate scientist Malte Meinhausen explains why we will need to use technology to suck CO2 out of the atmosphere.

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Technologies that remove CO2 emissions from the atmosphere could become central to our effort to combat dangerous climate change, a new Australian study has found. The study, released on Wednesday by The Climate Institute, follows up on an IPCC low-carbon technology report, and includes a world-first examination of the role of carbon removal technologies in national climate policy scenarios.

Using modelling by leading economics firm Jacobs SKM, the report finds that bio-energy with carbon capture and storage (bio-CCS) using food wastes, biomass, or crop residues, could remove and displace about 63 million tonnes of CO2 equivalent (MtCO2-e) annually by 2050, as well as generate 12 per cent of the country’s electricity.

However, without it – and with carbon dioxide levels now 40 per cent above pre-industrial levels – the research warns Australia could face an increase in climate action costs of up to $60 billion to 2050.

In this interview, Climate Institute deputy CEO Erwin Jackson talks to Dr Malte Meinshausen – senior researcher at the Potsdam Institute for Climate Impact Research, Germany and director of Australian-German College of Climate & Energy Transition, University of Melbourne – about why bio-CCS could become so crucial in the battle against climate change.

Erwin Jackson: What does the latest science tell us about the carbon budgets required to avoid a 2°C or 1.5°C increase in global average temperature?

MeinhausenMalte Meinshausen: That we have very little time left. The carbon budget would still be quite large if we weren’t trapped with all the existing fossil fuel infrastructure that causes us to ‘eat’ around 38 GtCO2 [billion tonnes of CO2] per year from the remaining budget. In fact, at the moment, we are eating ever larger pieces of the cake each year… and differently to eating a real cake, our appetite for more carbon doesn’t appear to be sated. The more we eat per year, i.e. the more fossil fuel infrastructure we build to meet our energy needs, the hungrier we are for more.

The latest science – from the just-released IPCC report – confirms that the total global budget that gives us a good chance of staying below 2°C is around 2,900 GtCO2. Until 2011, we had emitted around 1,900 GtCO2 of that budget. And every year thereafter we’ve emitted around 38 GtCO2. That leaves us with around 900 GtCO2 left from 2014 onwards, an amount that we are going to consume in just under 25 years, if emissions stay at today’s levels. Thus, it is time to slow down with our emissions, if we do not want to be faced with lots of costly stranded assets, such as fossil fuel power plants retired at young age.

For 1.5°C, the budget is going to be much smaller. Even under very high emission reduction rates, there is a relatively high risk that we could overshoot 1.5°C. However, in this scenario, we could bring average temperatures back down again to 1.5°C by the end of the century. Roughly speaking, the carbon budget for such a 1.5°C pathway is going to be half of the 2°C one.

EJ: What role could carbon removal technologies play in the task of meeting these carbon budgets?

MM: Unfortunately, it seems that even under the 2°C scenario, one day we will have to be sucking the CO2 out of the atmosphere that we are now putting in. Of course, not emitting that CO2 in the first place would be the far cleverer option. For a scenario with likely chances of staying below 2°C, like the lowest of the IPCC scenarios, the so-called RCP2.6, around half of the models suggest that by 2070/2080, we are going to need zero or net negative CO2 emissions. And even in scenarios where the gross emissions are slightly above zero, it seems likely that we won’t make a 2ºC scenario without those carbon removal technologies one day. Of course, the big challenge is to implement them wisely so that conflicts with other sustainable development goals can be avoided or minimised.

EJ: What do the climate and energy scenarios tell us about climate change if carbon removal technologies are not available?

That we still might have a chance to stay below 2°C, if we take decisive action. However, it’s going to be a tough call. And it seems that we cannot hope for a good chance to get to 1.5°C without those carbon removal technologies. Thus, we need carbon capture and storage – but not in combination with fossil-fuel plants. While pilot projects of carbon capture and storage are often seen as a lifesaver of coal, we actually need the geological storage potential for use in combination with bioenergy to achieve negative emissions in the longer term. For the large point sources of carbon emissions, like large power plants, zero emissions is just not good enough in the long term. We need those larger power plants to be carbon removal technologies in order to offset a whole lot of smaller and/or mobile emission sources that we are not likely to be able to get rid of so easily.

EJ: What do you think are the biggest risks with these type of technologies, and what could be done about them?

MM: The biggest risk I see with bioenergy with carbon capture and storage is the potential for unsustainable use of biomass that could increase food prices and be a threat to biodiversity. There are a lot of competing demands on land areas and strong bioenergy demand can obviously impact on some of them. The task is to minimise those potentially negative side effects by going to advanced biomass production, such as using wood, agricultural waste products or algae. Rotating crop varieties is obviously important too. Clearly, there are limitations to the biomass we can produce sustainably, so the challenge is to invest as much as we can in energy efficiency and renewables to minimise the need for large biomass programmes.

Another risk is more about policy and vested interests in relation to CCS. The fact that most fossil fuel companies are interested in research of carbon capture and storage, as it is potentially a way to reduce emissions from fossil fuels, is a risk for the public perception of carbon capture and storage.

Arguably, the interest of fossil fuel companies is in the research, not the deployment of CCS, as long as there are no regulatory or strong market incentives. Thus, somehow, while it might be okay that some pilot projects are co-financed by fossil fuel companies, it is important to disentangle fossil fuels from CCS as we might otherwise have a strong inbuilt incentive to ‘never finish the research’. And public policy needs to take bold steps, such as requiring that any new fossil fuel power plant, if any, is ‘CCS ready’ or rather ‘CCS operational’ before receiving its operating license. The requirement for CCS operation of fossil fuel power plants would of course, tremendously spur the research into CCS and allow us to then quickly use that knowledge for biomass CCS plants. Such regulatory policy would need to be flanked by strong market incentives, i.e. keeping and increasing a price of carbon.

Finally, there is another risk of perception: It wouldn’t be wise to continue to emit CO2 on the false understanding that we invent one day the mop with which we can clean up the mess. If done wrongly, the use of large amounts of biomass could potentially do a lot of harm. If done carefully, it might be okay – and help to bring temperatures slightly down for a 1.5°C degree scenario or keep them below 2°C at the very least.

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  1. Keith 5 years ago

    It’s really important to shine a light on the costs of CCS, as adding ANY additional costs to fossil fuel generated power makes it even less economically viable… this will help a realistic discussion about the need to dramatically grow wind and solar efforts, which deliver energy cost effectively now.

    • klem 5 years ago

      They deliver almost nothing. Wind farms only produce power when the wind blows, and you can only sell their power when people are actually buying.

      The big joke about CCS is the lie that merely pumping CO2 underground will keep it there. Ask any mine geologist and they will tell you that thousands of underground cracks and fissure will ensure that it escapes. Even the gullible public won’t fall for that one.


      • Keith 5 years ago


        If you are interested in facts rather than thought bubbles, try this website

        This gives real time contribution of wind power to total power consumption in Denmark. At this moment wind is generating 1.9GW of power in Denmark of a total of 2.7GW power consumption … I don’t think that is nothing… heading up from 30% to 50% of Denmark’s total power generation (that’s 24 hr/day).

        Likewise, closer to home wind (with some solar) is now generating 30% of South Australia’s electricity needs. It would be the same up the east coast if there wasn’t political obstruction to renewable energy rollout.

  2. Motorshack 5 years ago

    I’ve been reading about bio-char for some years now, although I have yet to see anything really conclusive about how effective it might be as a technique for large scale carbon sequestration. Then again, it has been a while since I read up on the subject.

    In any case, what does seem clear is that on a small scale it can be used both to generate some energy from bio-mass and to produce carbon – charcoal, essentially – that can not only be sequestered in the soil, but which will actually benefit the productivity of the soil a great deal.

    The technology is also quite simple and inexpensive to implement, so gardeners and small-scale farmers might well put it to use with little trouble or expense. In fact, in many places this has been done for centuries already. It is just that until recently it was not so widely-known.

    Among the various issues in scaling up there would be the temptation to favor bio-char production over food production, and, as Mr. Munthausen noted above, that is likely to be an issue in any system that sequesters carbon derived from bio-mass.

    Another temptation would be to use the bio-char as fuel instead of sequestering it.

    After all, people have been using essentially the same chemistry for centuries to produce charcoal for use in metal working. The whole point of charcoal is that it burns much hotter than the original wood, because it is nearly pure carbon, so putting bio-char into the ground means voluntarily passing up on the use of a quite superior fuel.

    So, the trade-off here is the economic value of the fuel, versus the value of the improved soil productivity.

    Still, every little bit helps, and as part of a judicious switch to generally more sustainable methods of agriculture, it seems well worth a look.

  3. Mark Roest 5 years ago

    Hello Motorshack,
    Check out BioChar in the Amazon on YouTube; the cultures there built up about five-foot thick layers of soil that was very heavy in biochar. It lasts for hundreds to thousands of years, and it dramatically ENHANCES food production, especially with a Permaculture-arborculture approach. Any cellulose can be used. The carbon that is burned is carbon-neutral. Biochar production can be skewed in different directions, including capturing the released volatiles and liquids and making fuel with them, while still having biochar for carbon storage and fertility.
    The way to avoid problems is to do whole systems analysis of each ecosystem, soil, and crop type, and provide training to (and learn from) literally every current and wannabe farmer on the planet, in all aspects of sustainability, tailored to what they specifically have to work with. We now have the communication and information technology capacity to do this efficiently and intelligently. The result will be to come as close as possible to immunizing humanity against famine and climate chaos, in the face of the damage which as already been done.
    The way to pay for it is to finance the training and any outside inputs; the loans will be paid back via the increased prosperity of those who receive them — just like the solar leases, in which everyone benefits.


    • Motorshack 5 years ago

      I agree that on a comparatively modest scale there appears to be little doubt of the short-term value of bio-char.

      The open question in my mind is only how much it can scale up, and just what the limitations might be. The two obvious possibilities are that the soil might accept only so much carbon before bio-char starts to be counter-productive, and that too much focus on bio-mass for fuel might have bad effects on the food supply.

      The long term natural sequestration of CO2 happens when carbonates are formed, and the resulting compounds are so stable that it takes massive amounts of energy to break the bonds again. Pure carbon remains rather easily oxidized, so it remains to be seen how stable bio-char really is in the soil.

      That is to say, on a human scale, being stable for centuries may seem very stable, but in geologic terms that is still the merest blink of an eye. In contrast, carbonates tend to remain stable for millions of years.

      So, while I very much think bio-char might be useful to some degree, and for at least a while, it remains to be seen on what scale and for just how long.

  4. Mark Roest 5 years ago

    I don’t see my notes from the talk at Eco-Farm in January, but they were giving very large numbers. They also said it can be used to improve watershed vegetative cover, with trees growing 3x faster in one experiment. Basically, you can use it on much of the land surface of the planet, at least where people are, and people can return to rural lifestyles again (with a few other resources for leverage). Maybe 3 billion people making biochar part time, or specialists in their communities making it all the time, until the job is done?
    Re millions of years, my sense is that we can clean up our mess in a few hundred years, other than bringing back the extinct species. And we could always make the beds ten feet deep instead of five feet!
    We do have to be smart about it; different plants and soils react differently to biochar of different types and concentrations.

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