Parable of the Sharks

Alice believes sharks are the biggest problem facing humanity.

If you ask her, she'll tell you about all documented cases of shark attack. She'll tell you how it's definitely undercounted - random disappearances will be counted as drownings even if they were shark attacks. Or someone could actually drown but only because they were running away from sharks.

She'll tell you that population increases every year, mostly in warmer and so presumably more shark-infested areas, that most people live in coastal areas, so we can expect more shark attacks in the future.

She'll tell you that as people get wealthier, tourism increases, and more tourists means more possibility of shark attacks.

She'll tell you that even living far away from the coast doesn't guarantee safety, as some sharks live in rivers. And what stops sharks from swimming into canals and sewer systems really?

She'll tell you that direct sharks attacks are just start of the problem. Sharks will eat fish, causing famines or mass unemployment in fishing dependent regions. Panics caused by shark attacks might cause mass migration, and all that together increases likelihood of armed conflicts. The more you talk to her, the most every problem turns out to be related to sharks.

She'll tell you how we need global solution to shark problem. Armed guards on every beach. Shark radars. Maybe even security bars in every toilet so shark won't swim up to bite you in your most vulnerable moment. The more you talk to her, the more elaborate her solutions become.

And of course she'll happily provide links with evidence for all those claims.

Bob doesn't believe sharks are even real.

Which of them is less wrong?

A modest proposal for climate change treaty

For a moment, let's forget questions like whether rapid reduction of greenhouse gas emissions would be sensible or even possible, and about alternative approaches. What can we do if we're serious about reducing emissions really fast? Let's use perfectly logical method of elimination to see what's left once we eliminate the impossible.

First, it should be obvious that no country has either interest or ability to do it on its own, or even together with a small group of other countries. Let's say even as much as half of the world, at enormous cost, overhauled its economy to be entirely emission-free by the next year. Suddenly the world would have immense amounts of oil, coal, and gas without anyone there wanting to buy them. The price would drop, demand from the still-emitting part of the world would increase, and new equilibrium would be established - not necessarily at emission levels so significantly lower. As an added bonus, a lot of manufacturing and other carbon-intense industries would simply move - yes there are tax solutions to reduce this part, but modern governments are incapable of dealing with even outright tax fraud by major corporations, so I'm highly skeptical about that; and in any case it's only one part of the problem.

Kittens in poor countries will emit more CO₂ as they get basics like fresh water

What's worse - however small was the interest that the emitting countries had before, now their economies are much more dependent on cheap fossil fuels than before; they have new carbon-intense industries; and with emissions reduced by someone else they care even less about global warming than before. Just in case you think this scenario is purely hypothetical, stupid, and there's no chance of it happening - we had a mild version of it called Kyoto Protocol. Some developed countries agreed to barely stop increase in their emissions, and everyone else took advantage of the suckers. Total world emissions increased by 41.7% 1992-2008, with China's and India's more than doubling. America had a boom for SUVs and increased its emissions by 16.8% even though they could have cheaply avoided it all by just better fuel standards. Meanwhile a lot of manufacturing moved to countries without emission limits (Kyoto Protocol wasn't the main reason for it, but its clear which way its influence went on the margin).

Meanwhile kittens in rich countries emit CO₂ by driving big cars

And don't even hope for voluntary drastic reductions in emissions - China promised to increase its emissions by only 40% by 2020... and that's considered major progress. India won't even promise constrained increase - anyone wants to bet how much time it will take till their emissions double? Obama is free promise whatever he wants, he won't be able to pass anything meaningful through lobbyist-dominated Senate, and whatever little he manages to get passed, Palin's administration will revert anyway.

Such piecemeal solutions just won't do. We need to have everybody on board - either voluntarily or by force. We can temporarily excuse very small or very poor countries, but there's simply no way to have a meaningful reduction treaty without developing countries like Indonesia and Pakistan on board. Unfortunately we cannot really force them to comply. If everyone else was cutting their emissions except for Sierra Leone, they could be beaten into submission with some economic sanctions or a few cluster bombs. Oh yes, I'm curious how willing are pro-emission-cutting folks to bomb countries which continue emitting? But even if we're willing to bomb, short of World War III there's no way to force China or India to do anything, and good luck with even mid-sized countries like Algeria and Brazil.

Unfortunately the set of countries hardest to force into agreeing to severe emission limits is almost exactly the set of countries which emit the most and whose agreement we most need. Now while it wouldn't be entirely impossible for such countries to agree to severe limits out of concern for planetary common good, it's about as likely as a bird baguette-bombing LHC. One such event per century and we already had ours. No, any realistic treaty must pander to biggest emitters. And here's my modest proposal:

Let's make the best estimate of what everyone's 2010-2020 emissions would be without a treaty. Subtract desired percentage. That's how much permits everyone gets, now go and trade.

Yes, it means rich countries get to emit a lot more than poor countries. And less efficient countries like Australia get to emit more than more efficient counties like Japan. And countries which were going to cut anyway like EU get to emit less than countries which weren't that committed like USA. It really sucks. But do you think you can have them agree to such limits otherwise? If poor countries want to increase their emissions - and they'd all love to do that, they will have to buy emission permits, with hard money. By the way targeting 2020's emissions or such is necessary as there's no way to get India to agree to 2010's emissions, let alone EU's favourite 1990's level - well we could bribe them, but then we can as well give them emission permits as a bribe.

It would have to be enforced hard - every country which tries to emit past their limits must be made to suffer. Because the treaty is advantageous to all powerful countries, as long as the poor countries are divided it wouldn't be too hard to enforce - definitely not anywhere as hard as enforcing it against China or USA. Threat of economy-crippling trade sanctions would absolutely necessary, they would most likely have to be actually applied a few times or the threat wouldn't work. It might very well require some bombing or even an outright invasion every now and then. But surely, there will be plenty of volunteers to fight for the planet, right?

Volunteers to invade countries emitting too much CO₂, artist's conception

Now the Guardian/New York Times reading crowd will surely reply "what about social justice" and nonsense like that. But first - how likely is it that Chinese Politburo or American Senate or Indian voters wanting to finally get their Tata Nanos are going to care about your idea of social justice? You can probably guilt them into parting with some of their money or emission permits, but there are hard limits on how much you can get - they have all the power, and countries like Tuvalu have none. And second, I find social justice arguments unconvincing and annoying. Some arbitrary class of people - in this case those who happen to be born in developed countries now - are blamed for what their grandparents did. Somehow this is always selective liberal self-hatred - you'll never see the New York Times blaming modern Arabs for their ancestors running African slave trade, but affirmative action following the same logic against white people is somehow considered fine. And only negative externalities of Western economic growth are considered!

What are total externalities of Western economic growth, starting from Industrial Revolution and its coal? Yes, carbon dioxide levels in atmosphere increased, and so did sea levels; but standards of living of everyone are drastically better than they were in 1800, not only in rich countries. Back then an average Indians lived 25 years (it's 65 now), one baby in three didn't last until its first birthday, hereditary dictators ruled the world, nobody could read, people were forced to marry their cousins at age of 12, and wars were a constant fact of life. Now we're all healthier, richer, safer, longer-living, and more free than ever. We're even far smarter than our ancestors, all thanks to modern economy!

You think it would be better to be a Medieval serf in a low-carbon economy than live with some temperature increase? If so, there are still a few places where you can fulfill your serf dream. If not, stop the bullshit that industrial development had net negative externalities. They were highly positive, and in fact it would be more "socially just" for poor countries using technology developed by us to pay us - something they will actually do if my modest proposal passes.

Poverty begets corruption. Corruption begets poverty.

On the other hand giving poor countries huge emission permits is not only politically unrealistic, it would also have severe consequences. Poor countries have almost all highly corrupt governments. Giving Angola free money or valuable emission permits wouldn't do much good to an average Angolan, but would surely make their politicians rich. It might also start a few coups, as which general could let an opportunity to get a tens of billions of dollars pass just like that. We have long history of throwing money at the problem - and it doesn't matter if it's aid, loans, or payment for oil and other resources - the end result is authoritarian corrupt governments and frequent military coups.

There's one more issue here. With perfect knowledge carbon tax and carbon permits are equivalent. But our knowledge of the future is highly uncertain - carbon tax means unknown emissions but known price - and is in every way better for the economy, as predictable long term prices make investments in reducing emissions safer; while carbon permits make emission known but price highly unpredictable. Now's the good bit - if technology optimists like Krugman and the entire Guardian/New York Times crows are right, permits will get very cheap very quickly, so amount of money poor countries will have to pay will be fairly insignificant - they might be even better off on the net thanks to new technology developed thanks to incentives for emission cutting. It's not entirely implausible, as that's what happened with sulphur dioxide cap and trade. On the other hand if energy pessimist like me are right, and technological progress will be too slow, poor countries will have to pay a lot. But that shouldn't concern you because you don't believe it could possibly happen, right?

Timing of peak CO2 emissions

I previously argued (1, 2, 3) that we can expect peak CO2 emissions around 2050. Copenhagen summit draft calls for peaking before 2020. Now it's not entirely impossible, but I would say it's quite unlikely.

Here's a quick list of my assumptions, and how timing of the peak, size of warming, and likelihood of geoengineering would change if they were wrong:

• Economic development of poor countries - faster development means more emissions. As this is the main driver of energy demand for the next few decades in my analysis, much slower development of poor countries will indeed move the peak a lot earlier. The consequence of slower growth is economic genocide, and it's far worse than anything climate change could do, with or without geoengineering. It's not a theoretical possibility, economic genocide is happening right now.
• Correctness of climate science - putting Climategate fraud accusations entirely aside, IPCC has ridiculously wide confidence intervals. Their A1 scenario which is closest to what I describe here expects likely temperature growth to be between 1.4C and 6.4C by 2010, and their likely means merely a 66% confidence interval. If you know anything about science, "95% confidence" turns out to be wrong more often than not, and these estimates are merely scenarios conditional on countless assumptions, not actual forecasts. So what IPCC is saying is essentially "it will get hotter, we have no idea whatsoever by how much". If warming turns out to be on the low end of IPCC estimates, we'll likely see slower adoption of technologies to reduce CO2 emissions, and no geoengineering. If warming turns out to be on the high end of IPCC estimates, we'll likely see faster adoption of emission-reducing technologies, and massive scale geoengineering will be as inevitable as I predict. This is not as relevant as it seems as timing of CO2 peak depends on decisions we'll make in the next few decades, long before we find out 2100's warming.
  
• Technological progress - faster technological progress can result in lower emissions. If we get breakthroughs in cheap solar energy, battery technology, algae biofuels and such, it might result in much faster peak, maybe even before 2020. But I wouldn't rely on this, a lot of money was spent on these technologies and progress has been slow - what we need is not just some incremental progress which we'll undoubtedly see, but huge breakthroughs and really fast.
  
• Multicentric world - if we had a world government, we could just take a vote, set up whichever emission caps or taxes we wished, problem solved. If we had a small number of important powers like we do now, we could get them to agree on some flawed solution. But the world seems to be evolving towards multicentricity - right now only US, EU, and China matter, plus maybe Japan, India, and Russia a bit - but in the future other countries will probably count a lot too - and the more players you have, the harder it will be to reach meaningful agreement.
• Economic development of rich countries - CO2 emissions per capita don't increase significantly past certain level of income, so it won't matter much either way.
  
• Demographic growth - faster growth means more emissions, but uncertainty about 2050 population isn't that high, so it can only have modest effect.
• Attitude towards nuclear energy - if people become more supportive of nuclear energy, it will reduce CO2 emissions somewhat.
• Policy of US, China, India, and the entire developing world - matters a lot, as they are current and future main emitters, they have a lot of demographic and/or economic growth ahead, and it's highly uncertain what their policies will be.
• Policy of EU - matters very little, as EU is already highly efficient for GDP it has, has little economic or demographic growth, and it can be relied on to do further reductions no matter what others will do.
  

Politics

And regardless of those, the most important factor is politics - global warming is a very unusual situation in which not only everybody's emissions affect everybody equally (straightforward externality / tragedy of commons), but also everybody's current emissions only affect people living in far future. We're asking for 2009's Americans to make significant sacrifices for the sake of 2100's Bangladeshis. 3000's Bangladeshis even, as IPCC says that "anthropogenic carbon dioxide emissions will continue to contribute to warming and sea level rise for more than a millennium".

Let's take an outside view, and make a reference class forecast - in situations in which current sacrifices of people living in one country could make a difference to people living in entirely unrelated country a century ahead - how often were the sacrifices made? To the best of my knowledge the answer is a reliable never. It just doesn't happen. If one country like EU now (and to not that significant extent) were to sacrifice money to limit its emissions, others would just take advantage of cheaper fossil fuels due to reduced demand and burn more of it.


In theory a global carbon emission market could be established, but good luck getting everyone to agree on allocation of emission rights, or income from their sales. The more severe the cuts, the more expensive will emission rights get, and the worse will the fight be. If we allocate most rights to rich countries, poor countries will correctly complain that it hinders their economic development. If we allocate most rights to poor countries, it will amount to massive transfer of wealth from the rich to the poor, and good luck getting voters to agree to that.

We're talking about tens of trillions of dollars. It's not a metaphor, just the proposed American system is estimated to be valued $80bln / year - $80bln times 40 years and 5x (world emissions / American emissions), it will be worth $16 trillion, and growing as supply gets restricted and demand grows due to economic development. How will these tens of trillions of dollars in either emission rights or auction profit receipts be allocated? Yes, good luck with that.

The alternative is not caring about greenhouse gases emissions, and geo-engineering the temperature growth away if need be.

Why CO2 emissions will not fall before 2050

In my previous posts I explained why emissions are unlikely to fall below current levels before 2050, and why due to peak heating occurring long after peak emissions we do have a very long term problem. Conclusion being - geoengineering is pretty much inevitable.

In this post I'd like to talk about two things - what the world will look like in 2050, and the Climategate.

First, the Climategate. As shown by the leak, scientists from East Anglia University engaged in some highly unethical practice, such as knowingly fudging data to support their thesis, violating FOIA and hiding data to the point of deleting it to avoid release, and organized bullying campaigns against scientists with the opposite views. This makes them bad persons, and if God existed, they'd suffer in Purgatory for it / or got shitty reincarnation in the next life / or something like that. Fortunately for them there is no God, so they will get off scot-free with it.

But this behaviour, while highly unethical, doesn't really seem to change the main conclusion of IPCC reports that anthropogenic releases of greenhouse gases have caused significant warming, and are likely to cause a lot more in the future.

The only consequences for climate predictions I can think of is that it might damage people's opinion of credibility of climate change science disproportionally to the breach of proper scientific practice (which did occur, but were fairly minor), thus reducing political will to act on climate change, and increasing the problem. But then, I doubt the damage will be that big.


Now to the main subject - world in 2050. There's no question that we'll stop emitting ever increasing amounts of greenhouse gases at some point. We already have at least four ways to entirely solve the problem even without any significant technological breakthroughs: nuclear, solar thermal, solar photovoltaic, and wind. But the question of when is a big one, and I doubt it will happen soon.


As I wrote in previous blog posts, in 2050 population will be around 9-10 billion, per capita GDP will be around current EU levels, and so will per capita energy use. But energy use and carbon emissions are not that closely connected - there are gains to be made in efficiency, both nuclear and renewables emit little in terms of greenhouse gases, so that doesn't directly imply much about per capita CO2 emissions (nor emissions of other greenhouse gases).

Let's make a simple table - what would have to change for 2050's CO2 emissions to be equal to 2009's CO2 emissions. For simplicity let's assume every country's per capita emissions will be the same for now. If some countries don't take their share of the burden, others will have to.

Country	Population (mln)			CO2 emissions (mln ton)			CO2 emissions per capita (ton/person)
	2009	2050	Change	2009	2050	Change	2009	2050	Change
China	1334 [19.6%]	1462 [15.7%]	+9.6%	6103 [21.5%]	4458 [15.7%]	-27.0%	4.57	3.05	-33.3%
USA	308 [4.5%]	397 [4.3%]	+28.9%	5752 [20.2%]	1210 [4.3%]	-79.0%	18.68	3.05	-83.7%
EU-27	499 [7.3%]	424 [4.5%]	-15.0%	3914 [13.8%]	1293 [4.5%]	-67.0%	7.84	3.05	-61.1%
Russia	141 [2.1%]	104 [1.1%]	-26.2%	1564 [5.5%]	317 [1.1%]	-79.7%	11.09	3.05	-72.5%
India	1173 [17.3%]	1572 [16.9%]	+34.0%	1510 [5.3%]	4794 [16.9%]	+217.5%	1.29	3.05	+136.9%
Japan	127 [1.9%]	109 [1.2%]	-14.2%	1293 [4.5%]	332 [1.2%]	-74.3%	10.18	3.05	-70.1%
Other countries	3214 [47.3%]	5253 [56.4%]	+63.4%	8293 [29.2%]	16021 [56.4%]	+93.2%	2.58	3.05	+18.2%
World	6799 [100.0%]	9322 [100.0%]	+37.1%	28431 [100.0%]	28431 [100.0%]	+0.0%	4.18	3.05	-27.1%

Data sources: emissions, population projections. EU-27 is used as European Union will most likely expand before 2050, and I don't want considerations like that to complicate matters.

Right now just six big entities - China, India, USA, EU-27, Russia, and Japan - emit over 70% of global CO2. But poor countries will develop, and this means more emissions. India's emissions are ridiculously low now - due to poverty - but once Indians get richer they will want cars. They will want pretty things. This will use energy, and this will emit CO2. The same story will take place in the "rest of the world" category (which unfortunately mixes small rich countries with big poor countries, obscuring the change).

What kind of emission cuts will the big emitters have to do just to counteract population growth of the world and economic growth of poor countries? Assuming the burden will be equally shared, USA will have to cut by 83.7%, or to 1/6th of current per capita levels. EU, Japan, and Russia will have to cut by about 2/3 per capita, and even China will have to cut by 1/3 per capita, in spite of so much economic development still being ahead of them! Other countries will have a mix of increases for the poor, and very significant decreases for the rich.

Now how likely is this scenario? I quite doubt we'll actually achieve equal sharing of burden.  Cuts for developed countries people talk about tend to be around 15% levels by 2025, so presumably around 40% by 2050, and even these are best case scenarios.

Intrade thinks that odds of any cap and trade system being established in USA by 2011 is about 50:50, and that says nothing about levels of caps, and severity of loopholes passed due to industrial lobbyists' money. After that it's Palin's administration as Krugman says, so don't hope for any meaningful limits. In general, people vote for current party when economy is good, and vote against current party when economy is bad, no matter who's guilty. Current predictions of American unemployment for 2012 are so high, that Democrats are very likely to be voted out of power unless they get their act together.


Anyway, 40% by 2050 is nowhere near enough to even keep 2050's emissions equal to 2009's! So rich countries, especially USA, are not providing the leadership here. What are the chances that poor countries will voluntarily take most of the burden of reducing carbon emissions all on their own? I'd say extremely slim.

And, most importantly... even if reductions from the table did happen, and 2050's emissions were at 2009 levels and falling, this still leaves us with massive global warming problem as peak warming happens long after peak concentrations, and peak concentrations happen long after peak emissions.

What brings us to where we started - there's simply no realistic scenario under which geoengineering can be avoided.

Inevitability of geoengineering, part 2

In my previous post, I explained why geoengineering to counteract global warming seems inevitable. To summarize, data suggests that between 2009 and 2050:

• World population will increase by about 45%
  
• Poor people are getting a lot richer, average wealth will increase by 200%
  
• This means they will use a lot more energy than now
• Neither renewables nor nuclear power seem likely to be able to replace them by 2050, at realistic growth rates
• Therefore only plausible source of that energy are fossil fuels, and we already have plenty of examples of countries drastically increasing their fossil fuel use and CO2 emissions extremely quickly.
  
• Reduction in energy use by rich countries is nowhere near big enough to counteract this
  

What changes around 2050?

• World population is expected to more or less flatten out around 2050. We're already adding fewer people each year than during peak growth, so growth is sublinear, let alone expecting it to be exponential. Long term projections need to be taken with a pinch of salt, but it's as safe as it gets to expect much slower growth in second half of 21st century than now.
• While world economy will keep growing, average GDP per capita will be more or less where EU levels are now, and energy use past this level doesn't increase that much.
• In all likelihood, sources of energy other than fossil fuels will be far better developed than now, so responding to any new energy needs by more renewable energy instead of by more coal power plants, will be much more likely.

Now I don't know exactly when we will have peak CO2 emissions, and at what level - somewhere vaguely around 2050, and at levels twice current seems likely, as decades before it will have much higher pressures to increase fossil fuel use than decades after.

The first problem, is that peak CO2 concentrations will happen long after peak CO2 emissions. Here's a random graph with emissions on the top, and concentrations on the bottom, color-indexed. In all scenarios, including almost immediate halving of emissions, peak is somewhere in 21st century, but CO2 concentrations keep growing long past 2300, peaking hundreds of years from now!!!
Now I don't actually believe CO2 emissions will be falling that slowly - once we figure out how to use renewable energy cheaply, we'll be able to switch almost all our use to it, so peak concentrations will be somewhere during 22nd century.

It gets worse - many effects of CO2 concentrations, like temperature change and ocean acidification, lag it significantly. So peak warming and peak acidification will occur much later than peak concentrations. With 2050 emission peak, and 2150 concentration peak, we might have 2250 climate change effects peak. (last figure completely made up, as it depends on too many details, different effects have different lags, and nobody makes serious estimates that go that far into the future). So even with a lot of optimism about alternatives to fossil fuels, we will have to deal with massive effects of global warming.

This gets us back to geo-engineering. No matter what we do now, short of a genocide and collapse of global economy (world economy grew during the recession, and fell only a few percents in the worst hit countries; this isn't the collapse I'm talking about), our choices are geo-engineering and adapting to higher temperatures.

Disclaimer time

Now disclaimer time. I'm making the common mistake that anthropogenic CO2 emissions are responsible for all global warming. This is not true - added CO2 is only 2/3 of it, the rest being methane, nitrous oxide, CFCs. But there are good news here - their lifetimes in atmosphere are much shorter - while we're talking tens of thousands of years for CO2, it's only 12 years for methane, and about 100 for nitrous oxide and CFCs, so peak concentrations will occur relatively quickly after peak emissions. And in fact, peak concentrations of methane and CO2 seem to have already happened or be happening about now. In longer perspective global warming problem is CO2 problem, with only small methane and nitrous oxide contribution.
The second disclaimer is that there are two kinds of geoengineering - solar radiation management (stratospheric sulphides, cloud seeding, albedo changes and such), and carbon capture and storage.

With solar radiation management we let warming happen, and create equal negative effect.

With CCS we could pull more CO2 from atmosphere than we're emitting. If we went this way peak concentrations might happen much faster after peak emissions than otherwise, and due to rapid fall in concentrations peak warming will be earlier and smaller.

I'm mostly talking about solar radiation management, as we already know how to cool down the planet with current technology and for ridiculously small money; while CCS solutions don't seem to be anywhere near scalable enough soon enough.

Any alternatives like fussion power, nanotech, and new kinds of renewables that people love to talk about won't seriously affect emissions until long after 2050 even in the most optimistic scenarios.

Inevitability of geoengineering

I want to write a quick post showing some arguments about inevitability of large scale geoengineering which I find extremely convincing. I'm sure I won't convince that many people, most have made up their minds already.

First, look at list of countries by CO2 emissions. In 2006 global emissions were 28.43 billion tons per 6.55 billion people, or 4.34 ton/person. World population is still growing and is estimated to stabilize at levels around 9.5 billion for 2050-2100, which is the time in question.

Now let's see what would happen if everyone got to current European standards of living, and European CO2 emissions, which are 7.84 tons/person. This would result in CO2 emissions of 74.5 billion tons, or 2.6x times current levels. This number is already quite optimistic - it makes a huge assumption that all countries with higher CO2 emissions like US, Japan, Canada, Australia, Russia etc. scale them down quite considerably.

Now a brief discussion is in order on why numbers like that are relevant. First, I assume that there won't be a massive genocide, or nuclear warfare, or pandemic, or anything else that could drastically reduce population levels. The last time there was a significant reduction in population levels was 1340s. None of the world wars, or any other events even stopped population growth - in fact people tend to reproduce a lot more during times of crisis, than during times of peace and prosperity, so it would need to be the biggest war, pandemic, or other kind of failure in history to significantly reduce population levels. This assumption is probably the safest.

The second assumption is that the rest of the world will grow quite quickly. World GDP/capita is currently $9,774 PPP. EU GDP per capita is $30,513 PPP. If world economy grows at per capita rate of 2.8%, then by 2050 world average GDP will reach current EU levels. This coincidentally is almost exactly annual per capita growth rate of the world economy of the last 30 years. Unlike with population, where predictions are quite solid, here there are more reasons why growth could be significantly slower, or significantly faster than predicted. We just had a completely unexpected global recession for a fairly obvious example. And not so long ago we had massive completely unexpected boom in China and then India, so it can go both unexpectedly badly and unexpectedly well. Still, 2.8% is a pretty decent first estimate.

I want to write a bit more on the subject of economy. Many people are sceptical about the idea that the "poor" countries will ever attain levels of economic development seen in rich countries. But the rich-poor divide is illusory. As you can see yourself with Gapminder, the divide is long gone and most countries are in the middle. World average life expectancy today is higher than in most richest countries in 1950s years ago. World average life expectancy in all but one countries is higher than world average 100 years ago - all that in spite of wars, malnutrition, malaria, HIV, and lack of clean water in many of them! Life in countries considered by many to be "permanently poor" is vastly better than it was in Europe of your grandfathers, and rapidly improving. To think it will somehow suddenly stop is to ignore history.

Development can happen extremely rapidly - world's largest CO2 emitter has been China for a few years now, per capita emissions of which increased by factor of x2.2 between 1990-2006. Likewise for India, growth was x1.6 during that time. Even for big countries not typically associated with rapid growth you have high growth - x4 for Vietnam, x2.4 for Thailand, x2.3 for Malaysia, x1.9 for Indonesia, x1.5 for Pakistan, x1.4 for Brazil and Nigeria and so on (and these are all per capita rates, their total emissions increased far more). Developing countries are catching up fast.

Let's look at past performance of world CO2 emissions. Between 1992-2007, world's emissions increased by 38% - mostly driven by rapidly developing countries like China and India. Even developed countries weren't terribly successful - US and Japan had significant increases in emissions, and EU's stayed pretty much even, and nominally decreased mostly due to early-90s' collapse of heavy industry in former communist member countries. Even if developed countries got their act together and implemented reductions that were agreed on in Kyoto Protocol, they would still be swamped by just Chinese increases, resulting in net emission increases.

And the outlook for the next couple of decades doesn't look terribly promising. Intrade markets, thin as they are (and forgive me lack of links, but their website is virtually unlinkable), think it's extremely unlikely that China and India will agree to any CO2 limits anytime soon, and have pretty low opinion on what reductions developed countries will agree to - chance of agreeing to 10% reduction by 2025 seems to be about even, and there's quite a big difference between agreement and implementation (especially due to possibility of accounting shenanigans of land use changes and such), and such reductions would be swamped by developing countries increase. And in any case the 74.5 billion tons number already assumes that developed countries average will get reduced to current EU levels.

If you hope on peak oil to make 74.5 billion tons/year kind of number impossible, not only peak oil doesn't seem to be happening, coal production grows insanely fast, and estimates of "peak coal" talk about mid 22nd century.

Alternatives to 74.5 billion tons a year

So with business-as-usual, we'll be emitting enough CO2 to get the entire planet stir-fried. What would be alternatives?

First, either outright genocide or indirect genocide by limiting economic growth of developing nations - remember that poverty kills hundreds of millions of innocent people and causes vast suffering. Not only is it unlikely to happen, it would be probably the worst scenario of all.

Second, learn to live in a warmer world. This isn't necessarily going to be as bad. It's hard to imagine anyone who would like to have their children die of malaria and diarrhea just to satisfy some rich smug liberals. People who measure costs of limiting CO2 emissions usually focus on limits in States, or EU - but this is nonsense! Big increases don't come from SUVs, but from bringing poor people to more civilized standards of living, and limiting that would be disastrous. Costs of just taking global warming would be much less than the genocide that would ensue to keep poor people in their place. I think this scenario isn't entirely implausible - there were quite a few cases in history where international cooperation completely collapsed, and in externalities cases like CO2 emissions, this is a possible result.

The third solution, and we're getting somewhere now, would be to sever the link between GDP and CO2 emissions. This is surprisingly hard. Yes, it's trivial to move from Hummer to Prius, but the problem is people who cannot afford either yet, but will want some means of transportation eventually. And they will want electricity - coming from coal most likely. The alternatives look pretty bleak - nuclear power, and large-scale hydroelectricity, both provide only 3% of total primary energy use now (or about 15% of electricity each). All fancy types of renewable energy together don't even add up to 1%. A surprisingly large amount of energy is "traditional biomass", or wood and agricultural waste used for heating and cooking (but then, estimates of it seem to vary wildly). Other than that, right now we're entirely dependent on fossil fuels.

A popular idea of high standards of living without corresponding increase in energy use seems pretty unlikely to me. Yes, we might be able to break the correspondence at some point, but energy use per capita in poor countries is so low, it's simply bound to drastically increase.

Much more promising path is energy generation without fossil fuels. Our best chance so far was with nuclear power. Unfortunately we suddenly stopped what looked like extremely rapid exponential growth in late 1980s after Chernobyl disaster - estimated 4000 people will die due to increased radiation exposure (much higher estimates based on linear no-threshold model can be safely ignored, as LNT model is known to be empirically completely wrong).
By ridiculously naive estimations, if this growth continued exponentially as it seemed to have up to Chernobyl, nuclear energy would provide around 20% of total energy production today, or half of all oil could be eliminated. Now this kind of extrapolation is ridiculously naive, but you should give it some thought.

So could we switch to nuclear at ridiculously rapid pace? We would need over 50 times as much nuclear capacity to generate enough energy to cover increased energy use by 2050, what seems ridiculously optimistic by any standards, not to mention nuclear proliferation issues. It looks somewhat less ridiculous when expressed as 10% a year growth (or doubling every 7 years like pre-Chernobyl), but it's just not going to happen.
There aren't that many renewable options. Current global energy consumption is 15 TW, and it will be about 39TW by 2050 by extrapolation. The only large scale renewable energy source we use, hydroelectricity, is nowhere close to our needs, and neither is geothermal really, if we look at what small fraction of it we can practically extract thanks to high local concentrations. We're left with just two then - wind, and solar. We would need to use 5% of all wind energy of Earth to fill the energy gap.

In 2008 wind power had 121GW of installed peak "capacity", and produced 260 TWh of energy (what corresponds to 30GW of actual production). It would require order of 1000x increase in wind power, or 19% a year growth, to make it fill the energy gap. And the actual growth is actually fast enough at 29% in 2008. But there are clear diminishing returns here - best locations will be taken, and massive subsidies cannot really scale to TW levels.

The other alternative is solar power. Just Earth-based solar is so plentiful that using even 0.02% of solar power now, or 0.045% of it in 2050, we can replace all of world's energy use. And it doesn't stop there, with space-based solar we can get numbers many many orders of magnitude larger. It would sort of need a space elevator, but we might get there by 2200.

Anyway, while solar is undoubtedly our long term future, it doesn't look that bright in the short term. There's only 15GW of solar thermal installed, and mere 0.6GW of solar thermal. And these are capacity numbers. We're talking x10,000 increase to cover the energy gap, or 25% a year increase, or x200,000, 35% per year for solar thermal. Now these numbers are actually what we see now, but as I said for wind, these are all based on massive subsidies, and there's no evidence that they're scalable to TW range at all.

By the way all this is based on assumptions that all energy is basically equal, and all greenhouse gas emissions is energy production. Neither of these are true - electricity is relatively easy to replace with renewables, at least if we ignore their intermittent character, but transportation much less so. And even with 100% solar electricity-based economy, there would still be some significant sources of greenhouse gases like methane from agriculture - so whatever we estimate here is bound to be overly optimistic.

With all this said, thanks to better energy efficiency, and widespread use of renewables, it's quite likely that humanity energy use by 2050 will be much lower than baseline number of 74.5 billion tons a year. On the other hand expecting it to be vastly lower than current emissions is just extremely unlikely.

And here comes the final solution - without genocides, without unexpected revolution in either nuclear power or renewables, we will have much more CO2 in atmosphere in 2050 than now. And due to massive lag it has, it will keep warming Earth for a very long time after we finally get our emissions to decrease. So if we cannot agree to live in warmer world, we have to geo-engineer to survive the next century without massive and irreversible environmental change.

Nature did some real life large scale geoengineering testing for us, and it works without major side effects (you probably haven't even noticed the experiment in 1991). Economic estimations put it in ridiculously cheap range - some schemes are estimated to cost just 375 million dollar a year, or just 17,000 Toyota Priuses (seems like a highly relevant unit of measurement) - for comparison replacing every American car with a Prius would cost 5 trillion USD, and it would still do very little towards limiting global CO2 emissions. And stratospheric sulphur isn't the only solution, just the one we have best data on (by the way it's not about polluting more, only about moving less than 1% of existing pollution to higher layers of atmosphere).

So the alternatives are:

• Outright genocide
• Indirect genocide by forced poverty
  
• Accepting the warming
• Increase in nuclear or renewable energy far beyond anything that can be realistically expected in this timeframe
  
• Geoengineering

Guess which one is the least bad?

Now I just need to blog on abortion, and I win blogging controversy bingo.