Wedging the climate

No one strategy can do all that we need to stop dangerous climate change. We need to follow several strategies simultaneously – but which ones? And are there solutions without nuclear power?

No one strategy can do all that we need to stop dangerous climate change. We need to follow several strategies simultaneously – but which ones? And are there solutions without nuclear power?

Many people in the climate change debate either champion one magic bullet as the answer (eg biofuels or nuclear power), or believe that nothing can be done without restricting growth. Others put their faith in new technology that doesn’t yet  exist. Or there are totally mad ideas like Bush’s plot to pollute our way out of this by making the atmosphere so murky with smoke, or put mirrors in space, so that the sun can’t get through. He hasn’t yet explained how agriculture is going to thrive in a sunless world, but I’m sure there’s a technology solution (growing crops in space on the other side of the mirrors?).

Back in 2004, two guys from Princeton University, Stephen Pacala and Robert Socolow, set out a series of potential strategies using current technologies. They started from the Intergovernmental Panel for Climate Change standard scenario that business-as-usual (BAU) will take us from current emissions of around 7 billion tons of CO2 a year (7GtCpa) now to around 15 or 16 GtCpa in 2050. To stabilise climate change below dangerous levels we need to get that 2050 number to between 6 and 7 GtCpa – and possibly much lower: Mark Lynas in Six Degrees believes we need to get it down to between 4 and 5 GtCpa.

Pacala and Socolow’s paper introduces the handy analytical concept of “Stabilization Wedges”, dividing the task into a series of actions each of which can grow over the next 50 years to save 1 GtCpa – alternatively, you can see a Wedge as something that can avoid 25 billion tons of CO2 emissions over that 50 year period. They came up with fifteen possible Wedges, and suggest that we need to follow at least seven: Lynas thinks we need twelve.

The possible strategies

These are the main possible Wedges:

  1. Improve average fuel economy in cars from 30mpg to 60mpg (while still growing the total number of cars in the world from 500,000 to 2 billion as in the business-as-usual (BAU) scenario)
  2. Cut average annual distance traveled by 2 billion cars from 10,000 miles pa to 5,000 – this obviously can’t be added to #1 without double-counting some savings
  3. Universal replacement of lighting and appliances with low-energy versions
  4. Efficient buildings: insulate etc to reduce heating and aircon use by one-third
  5. More efficient coal power plants: increase output efficiency in 2050 to 60% (from 32% today and from 40% in BAU) – again, obviously can’t be double-counted with all of the substitutions in the next four Wedges.
  6. Substitute gas for coal power: replace 1400GW of coal power stations with gas (this is a four-fold increase in gas-powered stations from today)
  7. Substitute nuclear power for coal power: add 700GW of nuclear power (double current capacity). NB: #5 and #6 together (or #7 and #8 together) replace essentially ALL coal power, so you can’t have all four of these wedges at the same time
  8. Substitute wind-power for coal power: add 2 million 1-MW-peak windmills producing power one-third of the time (50 times current capacity – covering 30 million hectares of land or sea)
  9. Substitute solar power for coal power: add 2 terawatts of photo-voltaic capacity (700 times current capacity – covering 2 million ha)
  10. Carbon capture and sequestration (CCS) at 800GW of coal or 1600GW of gas power stations – another obvious point, can’t be double-counted with #s 6,7,8, but probably can with #s 4,5. Pacala and Socolow also have two further CCS wedges attached to other types of power source, but these are essentially doubling up of the CCS strategy
  11. Hydrogen-fuel-cell-powered cars and trucks
  12. Biofuels: turn over 250 million ha of agriculture to biofuels (50 times current production) – this may have to be higher to generate fuel for the agricultural etc machinery to produce the biofuel. This is one-sixth or more of all the agricultural land in the world, and would produce about 34 million barrels a day of ethanol
  13. Decrease tropical deforestation to zero and establish 300 million ha of new tree plantations (double present size – obviously competes with #11, at least for land use)
  14. Apply conservation tillage (no plowing, cover crops, erosion control) to all cropland in the world

Some of these Wedges compete with each other, but most can be added together and still get both benefits. A few of them could be doubled up – for example we could choose to have two wind- or solar-power Wedges – but once you’ve replaced all the coal-power stations in the world you don’t gain by building more non-coal-power sources, and you have no possible gains from carbon capture and sequestration if there are no coal or gas-powered stations. And you certainly can’t reduce car mileage by half of current levels twice …

Some of the decisions here are more urgent than others: the most obvious problem is that any new coal-fired power station being planned now will quite likely still be in operation in 2050, so at the very least it needs to be planned in a way that will enable retrofitting of CCS technology once it becomes available.

So, what are the realistic options?

Homes and cars

Numbers 1 to 4 should be no-brainers: there is essentially no negative impact on economic growth with the possible exception of the economies of oil exporters, and more likely some increment in jobs created for building insulation workers and so on. If the peak-oilers (like me) are right, the reduction in use of oil for personal transport will anyway be enforced by lack of supply and consequent price rises. An aside relevant to another Webdiary debate: the UN predicts a doubling of the oil price to US$120 per barrel if Iran is attacked … that should push #1 and #2 along smartly. As noted, we can’t get a full Wedge from
both #1 and #2 at the same time, and we probably won’t replace every high-energy appliance in the world, so let’s call that three Wedges in total from reconfiguring our homes and cars.

Power generation

Numbers 5 through 10 require us to make decisions about the total mix of power generation at the year 2050. It would be unreasonable to assume that we can eliminate coal-fired power generation altogether, so let’s talk in terms of aiming for no net increase in coal-fired generation from the current level of around 1.6 Terawatt (1,600GW): it will be hard to keep down to this level, let alone below it, given the amount of coal-fired power already in use and under construction.

Applying efficiency increases per strategy #5 gets us only half a Wedge, because we have only half as many coal-fired stations to apply it to. Another half a Wedge can come from 700 GW of replacement gas-powered stations as in strategy #6. We can generate the remaining 500-700GW that would otherwise come from growth in coal-power with a mix of wind and solar (and/or geothermal power – not scaled in teh original paper) at about one quarter each of the numbers in strategies #8 and #9, leaving us with no need at all for increases in nuclear power, and gaining another half-Wedge.

Nuclear power as an alternative to the wind and solar generation is going to be  at least as expensive, dangerous both in its own right and as a potential terrorist target, and has a much much longer lead time before it can be brought into use at the levels we’re talking about, given that there are almost no plants currently under construction, and there is consequently a severe shortage of capacity and skills to get that construction under way even to replace the current nuclear generation capacity, let alone double it. So, while we’re at it, lets get another full Wedge-worth of wind, solar and geothermal, which would enable us to eliminate nuclear power from the planet altogether (though with no extra gain on the CO2 side).

Full carbon capture and sequestration on the new coal and gas plants per strategy #10 will in total get us another Wedge and a half. A more extensive program to replace or retrofit a combination of CCS and efficiency improvements in older and smaller coal and gas plants could get us a further Wedge.

There is probably also potential for at least another Wedge on applying CCS to plants producing hydrogen from coal and gas, and to plants producing fuel from coal – these were the extra CCS wedges in Pacala and Socolow’s original paper.

This gives us a total gain of five Wedges from reconfiguring power generation and the energy industry compared to the BAU scenario. 

As with the homes and cars segment, there are no obvious net losses of jobs here: the efficiency gains mean the world will burn somewhat less coal, but there are major investments and jobs to be had in the gas, wind and solar businesses – and the likely spreading of that half-to-one-million hectares of PV cells over millions of rooftops probably creates a lot of jobs.

Being parochial for a moment, total employment in Australian black coal mining is around 30,000 jobs according to the Australian Coal Association – out of 10 million jobs in total: it is likely that this will fall anyway through efficiencies (after all, after the sainted Mrs Thatcher broke the Miner’s Union in the UK, and simultaneously discovered the benefits of burning gas instead of coal, total jobs in coal-mining in the UK fell to less than 5% of the 1980 number). And 49,600 new jobs were created in Australia last month.

The hydrogen economy

This much-touted solution is multiply problematic:

  • the technology is currently unproven,
  • it can’t be double-counted with #1 or #2:
  • you need to add two wedges worth of nuclear, wind or solar to power the production of the hydrogen,
  • hydrogen storage and distribution networks will cost some trillions of dollars to build.

It is difficult to see how you can get a full or even a half-Wedge here before 2050, particularly when we’re already assuming that our cars in 2050 travel half the distance at twice the fuel economy – and the production of a huge (and potentially explosive /terrorist target) infrastructure would require a lot of energy in its own right. In my view this is for addressing the further Wedges we’re going to need in the second half of this century.

Agriculture and biofuels

Strategies 12 to 14 all impact on agriculture. #14 (conservation tillage) sounds pretty fanciful to me, at least in the terms used of requiring ALL agriculture to go this way – but let’s be optimistic and assume half a Wedge from this and more energy-efficient agriculture generally.

#12 and #13 obviously compete with each other in terms of the re-allocation of agricultural land: I’d say it would be pretty obvious that the world could not cope with the withdrawal of in total more than one-third of all food-growing land for biofuels and new forest plantations. Personally I’d junk the biofuel program entirely and try for the #13 scenario in full (zero deforestation and plant new forests), but then I’m a tree-hugger from way back. You may disagree, but I think we have to accept that at most we can get one Wedge in total from some combination of biofuels and forests.

I speak of the technology that is to come …

There may yet be another new technology we haven’t thought of yet that can help – though it probably isn’t smoke and mirrors. However, it takes around 25 years to get technologies from working lab prototypes to mass market adoption, so if it isn’t in a lab somewhere now it probably isn’t going to be around in big enough numbers much before 2050. What’s more, we’ve already looked at several technologies that aren’t actually working even in prototype yet at the necessary efficiency (clean coal, carbon capture and sequestration, hydrogen fuel cells), and made the assumption that we’re going to get enough of these working to get a couple of Wedges worth of benefit.

We have also looked for major savings in pretty much every sector of the carbon economy (homes, buildings, transport, power generation, agriculture). Any new new technology we haven’t thought of yet therefore potentially replaces some of the gains we’ve already counted. It would be optimistic to hope for more than another half-Wedge for this as-yet-unknown set of technology miracles, but let’s go a bit further and hope for a whole Wedge out of the blue …

As with the hydrogen-cell side, we anyway need those bright ideas to keep coming on down for the second half of the century, when we need to find a whole new set of Wedges to maintain stability in the carbon economy.

Really old technology

There is one other area of potential benefit from economic development in the third world, which will come from the substitution of modern power sources for heating and cooking by burning wood etc. This has impacts both in direct CO2 production and in deforestation, and could get another half-Wedge toward our target.

How are we doing so far?

Summing up where we’ve got to so far, we have:

  • three Wedges from more efficient homes, buildings, cars and appliances
  • five Wedges from clean coal, gas, wind, solar, geothermal and carbon capture (and we’ve got all the power we need while removing nuclear power from the planet)
  • a Wedge and a half from efficient agriculture, biofuels and carbon offsets in plantations
  • an optimistic Wedge from unspecified technological wonders that are to come
  • and half a Wedge from reducing local wood and dried dung burning in the third world.

The good news is: this is a total of ten Wedges, which is enough to get us from the 16GtCpa of the business-as-usual scenario back down to below today’s level of 7GtCpa – a 62% reduction. Nine Wedges would be enough to stabilise total atmospheric CO2 levels at or below the EU target of 550ppm by the end of the century, so we can get on to that track if we collectively do almost all of these things, starting now, and also do some other things we haven’t invented yet to keep on the right trajectory in the second half.

The bad news is: this is not going to happen unless there is a really marked change in attitudes by essentially all of the politicians in the world over the next five to ten years. On the other hand, essentially nothing we have assumed so far has any significant impact on economic prosperity, and may even have created growth and jobs compared to business-as-usual, so we can hope for this to sink in to even the ones like our own PM who would rather not hear this message.

The worse news is: if Mark Lynas is right, this isn’t enough, and 550ppm is heading us for the four-degree world, which is dangerous climate change indeed, and carries a high risk of triggering some of the nastier tipping points that take us on up (see How warm is Warming?). Remember that the long-term future in the four-degree world leaves Australia with no agriculture and substantially under water … If we can get all ten Wedges, we can stabilise at 450-500ppm, but that still leaves us with a high probability of warming to dangerous levels. 

Doing more …

To be sure of keeping warming to the merely uncomfortable, rather than the dangerous and unpleasant, we need another two Wedges.

There isn’t a lot more that can be done in power generation: if we get the full ten Wedges outlined above, we have reduced coal from 50% to 25% of total generation capacity, doubled its efficiency, and captured and sequestered most of the carbon produced. We’ve also taken renewables to what I suspect is about the maximum possible level, assuming we’ve eliminated nuclear altogether. There may be another Wedge to be gained there in the long tail of smaller power plants, but that’s probably for the second half of the century.

We probably should issue a warning to viewers here: the next paragraph contains adult themes and may shock some readers.

Getting those last two Wedges may require us to sacrifice some of the economic growth of the BAU scenario.

But before we descend too quickly into views of going back into caves or living in trees, let’s try and stay rational here: we’re not talking about sacrificing the lifestyle we already have, we’re talking about having less growth, a smaller increase on what we already have.

To take the most obvious example: the BAU scenario assumes that there are four ti
mes as many cars in 2050 as there are now. Do we really think that our lives would be better with four times as many cars on the road? OK, lots of those extra cars would be in developing countries rather than here, but can traffic in our cities stand even a doubling of the number of cars on the road without gridlock? And in fact almost all the cities in the world are as close to capacity, just as much in the developing world as in the rich bits. So let’s suggest we can maybe do with only twice as many cars as we have now, and we can have at least one Wedge more.

We can get another wedge in similar form by not acquiring quite as many new appliances, airconditoners, etc as we would otherwise do. Another option would be to substitute vegetable protein for meat in a substantial part of our diet – we’d probably produce more methane ourselves, but not in anywhere near the same quantities that cows and sheep do.

Bottom line: if we all get on board, we can still save the planet without sacrificing our lifestyle in any significant way – so why is there so much resistance?

What can we personally do to make this happen?

The key things here are:

  1. replace all your lightbulbs, appliances, cars etc with more energy efficient ones as they need replacing (we have fifty years here, and replacing them before they need it wastes energy too)
  2. don’t buy that second car (or a third one for the kids to use)
  3. travel less, and do more of it on public transport
  4. in particular, fly less (sorry – this is the hard one for me, too, with my kids currently resident in London and in Guatemala City)
  5. buy green power, and thus push your supplier toward making the changes in generation mix set out here
  6. try to choose locally-made and grown products, to reduce the carbon component from transporting what you buy to you
  7. buy carbon offsets from people who can prove they really are planting those trees etc we need for strategy #13
  8. look at this week’s New Scientist special and understand the whole thing better [NB the print edition only deals with 7 climate myths, whereas the online extends that to 26, so better to look at the online version]
  9. and last but not least, tell your political representatives that you care about this stuff and want them to care too – start on that by signing the GetUp petition here.

Over to you …



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