Category: The environment

Atmosphere, biosphere, lithosphere, hydrosphere, etc – everything about life and the state of this planet

How much carbon dioxide can we release?

Climate sensitivity is the amount of warming that would arise from doubling the concentration of carbon dioxide in the atmosphere. The IPCC estimates that it is between 2.0˚C and 4.5˚C, with 3.0˚C as the most likely value. They also warn that, because of feedback effects, “values substantially higher than 4.5˚C cannot be excluded.” Basically, this number refers to how many degrees of warming would arise from raising the concentration of CO2 in the atmosphere from the pre-Industrial level of 290 parts per million (ppm) to 580 ppm: 50% above today’s level of 385 ppm. The higher the number, the worse the consequences from any particular level of emissions.

We can combine that figure with the maximum amount of warming we are willing to tolerate and come up with a figure for how much more carbon dioxide humanity can release, all told. Using the 2˚C ceiling adopted by the European Union and endorsed by 200 of the world’s top climate scientists, Andrew Weaver worked out what those limits would be for different climatic sensitivities:

  • 2.0˚C sensitivity – 1314 billion tonnes (gigatonnes) of carbon – 4822 gigatonnes of CO2
  • 3.6˚C sensitivity – 661 billion tonnes (gigatonnes) of carbon – 2426 gigatonnes of CO2
  • 4.5˚C sensitivity – 484 billion tonnes (gigatonnes) of carbon – 1776 gigatonnes of CO2
  • 8.0˚C sensitivity – 163 billion tonnes (gigatonnes) of carbon – 598 gigatonnes of CO2

The 2˚C and 4.5C figures are the top and bottom of the IPCC’s probable range. The 3.6˚C figure is the one considered most probable by those running the University of Victoria climate model. The 8˚C figure illustrates the impact of much higher sensitivities on how much can be emitted.

Current annual carbon dioxide emissions about ten gigatonnes of carbon (36.7 gigatonnes of CO2) per year. Note that the figures above are how much CO2 can be emitted in total before the whole world becomes carbon neutral – certainly not about how much can be emitted before we need to begin cutting. Those totals need to include all future emissions from developed and developing states alike, between this year and whichever year the world achieves carbon neutrality.

The 4.5˚C scenario implies a peak concentration of 445 ppm – slightly lower than a commonly cited ‘safe’ level. Some people – notably James Hansen – have argued that an even lower stabilization concentration is necessary to avoid runaway climate change.

Unreliable Sylvania

The two selling features of compact fluorescent bulbs are higher efficiency (more light produced per unit energy) and longer lifespan, when compared to incandescent bulbs. We have already established that the first isn’t a concern for people actively heating their homes. My recent experience with the second is also rather negative. I recently replaced as many bulbs in my house as possible with fluorescents. In the month and a half that followed, four of the bulbs failed: those in my kitchen, on my back porch, and in my front hallway.

I have never had incandescent lights fail so quickly. It’s not clear what caused these ones to die so abruptly (A manufacturing defect? Problems with my power supply?), but it will definitely prevent me from buying Sylvania brand bulbs in the future.

Ethics embedded in economics

I recently attended a presentation on economic modeling, climate change, and the social cost of carbon. Initially, this was presented as a process where we took our best scientific information, fed it into our best economic models, and ended up with our best projections about how much harm climate change would do, and thus what the ‘social cost’ of carbon really is. The point I raised was that this approach is in no way divorced from ethical assumptions. Indeed, they are deeply ingrained in the economic models and have profound effects on how they turn out.

Here are a few of the most important aspects of that:

1) The discount rate: Nicholas Stern took a lot of flak for setting this value so low. Basically, it pertains to how much we value the welfare of future generations. The lower you set it, the more the welfare of future generations will affect your calculations. In financial planning, discount rates are often in the neighbourhood of 8%. That means we would be indifferent to having $X today or $X + 8% in one year. The trouble is, with a value that high the welfare of distant future generations becomes almost completely unimportant in your calculations. If we knew that climate change would instantly kill everyone alive in 100 years, using an 8% discount rate would make this fact largely unimportant in terms of working out what the ‘social cost’ of one tonne of carbon is today.

Of course, there are problems with using a very low discount rate as well. If we care as much about all future generations as about our own, we are compelled to put all of our wealth towards investments for them. After all, current spending only benefits us, whereas investment could increase the welfare of a potentially infinite chain of future generations.

In any case, the discount rate selected has a massive effect on what social price for carbon you end up with. Stern worked it out as about $85 per tonne. William Nordhaus, another economist, came up with a figure of $7, largely because he used a higher discount rate. This one choice has the power to massively affect any economic analysis of climate change.

2) The marginal utility of income Take $100 per year from Bill Gates and he will never notice. Take it from everyone living in Sub-Saharran Africa, and you would probably kill millions. Despite this, most economic models assume that a dollar is a dollar is a dollar. If melting permafrost makes us abandon a northern community, at a cost of $20 million, but the cost to Canadian industry of avoiding the emissions that caused it would have been $21 million, the economically optimal outcome would be to allow the community to be destroyed.

To some extent, this can be built into economic models. We can create a mathematical function for how useful each extra dollar a person gets is. If we use that ‘utility’ measure in place of a dollars measure, the impact of different choices on the least well off becomes more important. Actually doing so on climate change would almost certainly hugely increase the social cost of carbon, since the welfare of those threatened by sea level rise in Bangladesh and drought in Sudan would be considered on more equal terms to wealthy Floridians with property threatened by hurricanes and oil company employees hoping to exploit new fields in the Arctic.

In addition to having economic importance, this has massive ethical importance. An approach based on potential Pareto optimality supports any move that improves overall welfare. It doesn’t matter if the people gaining are residents of suburban Toronto while those losing live in villages in Ghana. In everyday life, we recognize that we cannot go around harming people just because we gain more from doing so than they lose.

3) Valuing catastrophic risks If we manage to turn the world’s carbon sinks into net sources, we will have created self-sustaining climate change. If that occurs at an accelerating rate, we will be facing runaway climate change, which threatens to cause enormous physical changes and mass extinctions – possibly including humanity itself. Integrating such possibilities into economic models requires a number of ethical assumptions. Even a very small possibility of such an outcome can have a giant influence on certain kinds of models; likewise, choosing to ignore such outcomes has highly ethically relevant effects.

In short, we cannot combine scientific and economic models and produce a technocratic answer about how much climate change should be permitted. We need to acknowledge and consider the ethical implications built into and arising from those models, we need to choose what kind of world we want to hand over to future generations, we need to consider how important we think responsibility for the problem is when allocating costs, we need to consider the special circumstances of the very poor, and we need to consider how big a risk of catastrophe we should really tolerate.

I think an honest examination of those issues, alongside the best climatic science we have, creates a powerful and immediate ethical and economic argument for change. It is virtually certain that – if they could speak to us – people fifty or one hundred years in the future would be screaming at us to do dramatically more than we are doing now.

May on the train

Kudos to Green Party leader Elizabeth May for using her campaign to draw attention to the unsustainable character of air travel. Rather than fly all over the country to court voters, she has opted for a far less carbon-intensive train based approach. One round-trip journey from Toronto to Vancouver emits about 1,700 kilos of carbon dioxide equivalent. A train journey emits about 730kg: about 60% less. That is not enough of a reduction for trail travel as presently undertaken to be genuinely sustainable, but it is a significant step in the right direction. People would also probably think more about long-distance transport if it took a few days rather than six or seven hours.

The linked CBC article does get one thing wrong, however. It says: “Other observers have pointed out it is probably cheaper than flying, too.” As discussed here before, taking the train seems to be more expensive. At present, a return ticket between Toronto and Vancouver is running for $1,390.20 plus taxes. WestJet provide the round-trip transport for $439.25 after taxes.

Temperature, humidity, and precipitation

The amount of water that can be dissolved in air changes as a function of the temperature. In general, this means that increasing the temperature of air by 1˚C increases how much water can be dissolved in it by 7%. The precise values for any temperature change can be calculated using the Clausius-Clapeyron equation.

This is relevant to climate change for two reasons. Firstly, water vapour is a powerful greenhouse gas. Higher temperatures cause more evaporation and allow air to be more water-saturated, thus permitting further warming. Secondly, increased temperatures affect precipitation patterns through changes in the water capacity of air. The general trend is towards more extreme precipitation, more drought, greater annually averaged precipitation in middle and high latitude locations, and decreased precipitation in the tropics.

Forget targets

The big picture on climate change is one of the composition of the atmosphere and the thermodynamic balance of the planet. It is a very complex and long-term story, some of which requires considerable scientific knowledge to grasp. The basics of it come out to this:

  • Humans are changing the climate.
  • Further change is profoundly threatening for humanity.
  • We need to stabilize how much greenhouse gas is in the atmosphere, and do so at a safe level.
  • This requires fast, deep cuts.

A lot of attention has rightly focused on emission targets and timelines: where we need to be by when to achieve the kind of outcomes we want. The trouble with this debate is that it is largely artificial. Candidate X might say: “Cut to 50% below 2000 levels by 2050” and Candidate Y might say: “Cut to 65% below 2000 levels by 2050.” The difference between the two outcomes would be important for the climate. At the same time, the difference between the candidates is actually much less about the targets and much more about the means of implementing them. Candidate Y might say: “Voluntary measures, technological progress, and magical future technologies will do the job” while Candidate X might say: “We will limit total emissions from our economy to 3% below this year’s level next year. We will charge firms for the right to emit this much. We will use that money to foster a transition towards a low-carbon economy.” Needless to say, the results of each plan will differ significantly by the time you get to 2050.

The critical thing right now is to bend the path of global emissions. Rather than moving ever-upward, it needs to turn downward and start the long decline towards a low-carbon economy. Achieving that is all about immediate measures, not about emission projections that delay most of the reductions for decades. While it is certainly cheaper to cut a notional tonne of emissions ten years out, it is also the case that starting the transition will be more difficult than maintaining it. As such, it would be good to see states and political parties competing over who will cut emissions more in the immediate future, rather than across timespans during which today’s leaders will be enjoying their retirements.

Of course, the political risks of cutting emissions now are comparatively large. When it becomes evident what that will involve, it might prove expensive and politically unpopular. Protecting the welfare of present and future generations might evoke the wrath of voters during the next election. Unfortunately but honestly, no politician can be expected to show such bravery. Even so, there is an opportunity to recast the narrative. Firstly, we need to stress that this transition simply needs to occur. The alternative to acting now is simply delaying to the point where the transition will cost more and the impacts of climate change will be more severe. Secondly, this is an epic opportunity for humanity and for individual states. We can finally move beyond a post-Industrial Revolution economy based on constantly borrowing from the welfare of future generations. We can create states and a global society than run on sustainably produced climate-neutral energy.

The action required to start doing so is needed immediately. Choose someone who promises to change something by next year, and turf them out if they don’t.

Comments? Counter-arguments?

Summer has passed

Some facts for the autumnal equinox:

  • The Earth has seasons because it orbits the sun while tilted 23.44˚ off the vertical axis.
  • This tilt varies with time, following a 41,000 year cycle.
  • At the maximum, the tilt is 24.5˚. At the minimum, it is 22.1˚. When there is more tilt, the difference between summer and winter increases. When there is less tilt, the seasons are more similar.
  • Along with the changes in the shape of Earth’s orbit (eccentricity – 100,000 year cycle) and the way the planet wobbles around the pole (precession – 26,000 year cycle), axial tilt (obliquity) contributes to the Milankovitch cycles – one of the major long-term drivers of natural climate change.
  • To learn more, look up Dansgaard-Oeschger events and Heinrich events.

Disclaimer: Yes, orbital and solar variations affect the planet’s climate. That doesn’t mean human greenhouse gas emissions don’t, nor that they aren’t the primary cause of the climate change presently taking place!

Spremberg clean coal plant

In Germany, Vattenfall is in the process of constructing a 30 megawatt (MW) ‘clean coal’ power plant. The plant will separate pure oxygen from air, burn coal in it, then ship the resulting CO2 to an injection facility 150 miles away by truck. The liquified CO2 will then be injected 3,000 metres underground in a depleted gas field.

The best thing about this project is that it will provide some real data about the feasibility and costs of carbon capture and storage (CCS). A 30 megawatt plant is a pipsqueak compared to the 500 and 1,000 MW coal facilities that are operating and planned. Nonetheless, this smaller plant should provide some useful information about timelines and cost structures. It will also establish how much of the total energy produced by the plant will be needed to produce the oxygen stream, as well as liquify, transport, and bury the CO2.

Too often, governments and industry groups blithely assert that they will sequester 10% or 20% or 50% of emissions by year X. At present, that is a bit like the Wright Brothers describing the economics of a major airline. It is only with the successful deployment of pilot plants that we will discover if ‘clean coal’ is actually a viable low-carbon source of energy or (as I suspect) a high-cost distraction from superior alternative approaches focused on renewables, efficiency, and conservation.

Confused about climate

I have a Google Alert set up that forwards news stories including the terms “Canada” and “Climate Change.” Every day, it provides a few very misleading items, usually published on personal blogs or the canada.com network: a group of publications including the Vancouver Sun, Province, and Chilliwack Times. A piece in the latter caught my attention the other day, written by Jack Carradice. It seems worth examining in some detail. It reads like a grab-bag version of grist.org’s collection of invalid ‘sceptical’ arguments.

Complexity and uncertainty:

One aspect becoming very clear is that the science of climate change is much more complex than many seem to believe and much of the science involved is not well understood. In fact, it is beginning to appear that we know little if anything about some of the factors related to climate change.”

This is true but misleading. As discussed here before, the core facts about climate change are now beyond dispute. The biggest uncertainties have to do with feedback loops, the timing of impacts, and specific higher-order outcomes arising from human-induced temperature change.

Carbon dioxide not the cause:

The notion that man-caused carbon dioxide emissions are the sole cause of “global warming” and that man can control climate change in any meaningful way has pretty much been proven as nonsense.

While it is true that CO2 emissions are not the sole cause of climate change, this statement is simply false. The Fourth Assessment of the IPCC – the most authoritative scientific assessment of climate science – concludes that “Warming of the climate system is unequivocal.” It states further that “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.” Non-CO2 factors that influence climate change include emissions of nitrous oxide and methane, as well as deforestation. The fact that there are non-CO2 contributions in no way diminishes our certainty that human carbon dioxide emissions cause the planet to warm.

The role of water vapour:

Some of the basic facts the public have not been made aware of are that water vapour is the primary greenhouse gas accounting for up to 90 per cent of the greenhouse effect.

Nobody denies that water vapour is the greenhouse gas with the largest effect. What one needs to remember is that the amount of water vapour in the atmosphere is determined by the temperature (just like how you can stir more sugar into hot water than cold). As such, water vapour magnifies the effect of CO2 emissions.

Natural emissions are larger:

Also that 90 per cent of annual carbon dioxide emissions come from natural sources and have nothing to do with the burning of fossil fuels.

Gross natural emissions are larger than human emissions, but they are balanced by natural absorption. Human beings add about 29 billion tonnes of carbon dioxide to the atmosphere every year through the burning of fossil fuels. Some gets absorbed into the deep oceans, but much endures in the atmosphere to cause warming.

Necessity of CO2:

It is not generally publicized that carbon dioxide is essential for plant life and without it we would all die of starvation.

Nobody denies this either, and you would need to be thick-headed to believe that climate scientists advocate the elimination of all CO2. As Carradice correctly points out, the natural greenhouse effect is essential for maintaining an appropriate temperature for life on earth. Of course, it is incorrect to say “Some CO2 is necessary, therefore the more of it around the better.” The lesson from one hundred years of ever-more-detailed climatic science is that there is good reason to fear the consequences of anthropogenic climate change.

Solar radiation changes:

The effects of changes in solar radiation also seem to be overlooked by many observers.

Not by the IPCC. The Fourth Assessment Report concludes that changes in solar irradiance produce 0.12 watts per cubic metre of radiative forcing. CO2 produces 1.66 watts per cubic metre, while methane, nitrous oxide, and halocarbons produce 0.48, 0.16, and 0.34 respectively.

Methane from Indian cows:

Methane is a much more powerful greenhouse gas than carbon dioxide… By some calculations if India reduced their population of sacred cows by 25 per cent it would reduce the amount of greenhouse gas going into the atmosphere by the same amount as taking every car and truck in Canada off the road.

These assertions oddly contradict others above. They acknowledge that both methane and CO2 are greenhouse gasses and that emitting them warms the planet. I couldn’t tell you off the top of my head whether livestock emissions in India are bigger than automotive emissions in Canada, but making the comparison requires accepting the basics of climate physics.

Climate has always been changing:

Forget the climate change hysteria. Climate has always been changing.

True. Indeed, if humans were suddenly dropped into many of the states the world has experienced, we would have a tough time surviving. There is every reason to think that long-term natural climate change might eventually produce conditions adverse for human beings. What anthropogenic greenhouse gas emissions are doing is accelerating those dangers enormously. Whereas the natural carbon cycle is largely a matter of geology, subduction, and volcanoes, we are liberating the carbon in fossil fuels at a break-neck pace.

In short, Jack Carradice’s piece is an orrery of errors: rife with every form of misunderstanding and misinformation. It is hard to imagine a ‘news’ story that would do a worse job of informing readers about the realities of climate and climate science. Some of the points are entirely valid, but they are woven into an incoherent tapestry alongside errors and distortions. The article says simultaneously that climate change isn’t caused by human activities and that it is, that more CO2 would be bad and that it would be good, that concern about climate change is misplaced and that it is valid.

Hopefully, readers of the Chilliwack Times will be discerning enough to reject Carradice’s muddled position and read something both accessible and accurate on climatic science, such as Andrew Weaver’s “Keeping Our Cool,” Richard Alley’s “The Two Mile Time Machine,” or Al Gore’s “An Inconvenient Truth.”

Plug-in hybrids, GM, and sunspots

The good news: General Motors is releasing a plug-in hybrid called the Volt. Plug-ins have the potential to seriously reduce emissions associated with urban transport.

The bad news: GM Vice Chairman Bob Lutz doesn’t believe carbon dioxide causes climate change. Apparently, is a fan of the utterly discredited “it’s caused by sunspots” theory of global warming.

Plug-in hybrids powered by renewable electricity are a green option, at least in comparison to conventional automobiles. It’s unfortunate that buying this one will help fund a company with a history of funding the bogus ‘debate’ about the causes of climate change.