Science – Page 100 – a sibilant intake of breath

Observing global oceans

A number of severe problems are facing the world’s oceans and the living things that dwell within them. There is the exchange of invasive species through shipping, worldwide overexploitation of fish stocks, the acidification of the ocean from increased atmospheric carbon dioxide, changes in salinity that threaten major ocean currents, and pollution (including eutrophication from chemical runoff). As such, calls for more extensive study seem quite justified. One group that has been making such demands is the Partnership for Observation of the Global Oceans (POGO). They have called for an expanded global monitoring system involving research ships, buoys, satellites, and animal tagging. Such a system should both help scientists to understand the operation of existing systems better and predict the future consequences of ongoing human activities.

One of the more interesting satellites in the process of deployment is Jason-2. It will provide data on sea level changes with unprecedented accuracy and coverage. Using a RADAR altimeter, it will determine sea levels to centimetre precision, measuring the 95% of all ice-free ocean areas every ten days. This is helpful because sea level is not constant or globally consistent: observing how it changes can improve the quality of weather predictions and climate models. The level of radiation in the zone where Jason-2 will orbit is intense. As a consequence, the projected lifetime of the craft is only about five years. If all goes well, it should be launched in February 2008 to replace the Jason-1 system, already suffering from multiple failures.

Understanding climate absolutely requires understanding the nature of the oceans, as well as the interactions between the hydrosphere (liquid water), cryosphere (ice), and atmosphere. Hopefully, a few billion dollars spent on oceanic research will yield understanding that can help to guide more intelligent action. Of course, having that transpire requires more than scientific certainty – it requires the personal and political will that have really been the absent element in ocean management.

Homeopathy is fraud

It astonishes me that anyone takes homeopathy seriously as a kind of healing. Essentially, the idea is to take a substance that causes symptoms similar to those a person has (hot pepper for fever, etc) and then dilute it to an enormous extent, producing a solution that is essentially water. The dilution can be so extreme that it becomes probable that no molecules of the original substance are in a dose of the ‘medicine.’ This is then given to people who are told it will somehow help to make them well.

The solutions given are basically just water and/or alcohol, so they are fairly unlikely to harm anyone. Of course, they are as likely to have a positive medical effect as sprinkling the credulous with fairy dust. Any benefit is purely the result of the placebo effect. The fact that giving someone anything and saying it will make them better actually does in many cases is well understood.

As such, it is a bit shocking that such practitioners stay in business and that anyone takes them seriously. People are being misled (perhaps not lied to, since homeopathy practitioners may believe this stuff) and charged money for something useless. If nothing else, consumer protection organizations should be vocally and persistently objecting to this nonsense.

Methane clathrates and runaway warming

Essentially a form of ice infused with methane, clathrates may seem an obscure topic for discussion. They exist only under extreme conditions: such as underneath oceanic sediment. What makes them significant is the sheer volume of methane they contain. While it is unclear what degree of warming would be required to induce methane release from clathrates, there is a very real possibility that such release could be self-reinforcing. Given the global warming potential of methane and the volume of the gas in oceanic clathrates, such a self-sustaining release could induce abrupt and massive climatic change.

As a greenhouse gas, methane is potent. Averaged across a 100 year span, one tonne of methane produces as much warming as 25 tonnes of carbon dioxide. Even worse, when atmospheric methane breaks down, it generally oxidizes into carbon dioxide and water. Taking into account secondary effects, the warming potential of a tonne of methane is about equal to 72 tonnes of CO2 (according to the Fourth assessment report of the IPCC). This is one reason people are so concerned about the climatic effects of meat production, as well as the reason for which methane capture projects are one of the more credible kinds of carbon offset.

Recent estimates hold that ocean clathrates contain 500-2500 gigatonnes of carbon dioxide equivalent: akin to 100-500 years worth of sustainable emissions. About 400 Gt of carbon dioxide equivalent is in the Arctic permafrost. If a substantial proportion of this methane were to be released, it would take the world into completely unknown climatic territory. As such, it is highly likely that the adaptive capacity of both humanity and existing ecosystems would be overwhelmed, perhaps to a degree akin to the Permian-Triassic extinction event. This is truly the nightmare scenario for climate change, though its probability cannot be accurately assessed in relation to any combination of human behaviours and natural variations.

The existence of such exceedingly dire possibilities affects economic calculations about climate change. While it may not be sensible to spend 20% of global GDP to avoid an outcome with a 0.1% chance of occurring, a strong argument can be made that heavy expenditure is justified in the face of catastrophic risk. It is not as though we have another planet to fall back on if this one gets rendered unfit for human habitation.

[Update: 4 February 2009] Here is a post on the danger of self-amplifying, runaway climate change: Is runaway climate change possible? Hansen’s take.

[Update: 19 February 2010] See also: The threat from methane in the North.

Four Economist articles on climate change

Sorry to post a bunch of links from one source, but this week’s Economist is unusually dense with worthwhile articles about climate change:

There is one on federal legislative efforts in the United States – focusing on the Lieberman Warner bill that has been dominating attention in the Senate. It isn’t as tough as a superior proposal from Bernie Sanders and Barbara Boxer, but it stands a better change of thrashing its way through committee and onto the Senate floor. Of course, even a bill that gets through the Senate would need to be made compatible with a bill passed by the House of Representatives and avoid being vetoed by the President. Even so, the kind of cap-and-trade bills that are appearing in the Senate may well be indicative of the kind of legislation to expect from the next American administration.

American states have traditionally been ‘policy laboratories’ and have often developed environmental policies that were later adopted federally. Examples include rules on automobile emissions and sulphur dioxide emissions which cause acid rain. A second article briefly discusses the Regional Greenhouse Gas Initiative (RGGI): one of the two most important regional initiatives in the US, along with the Western Climate Initiative. Again, this is more a sign of what may be to come than a hugely influential thing unto itself.

A less encouraging trend is demonstrated by an article on the increasing popularity of coal. What is especially distressing is that coal plants are even being built in Europe, which has gone further than anyone else in regulating carbon emissions. Clearly, prices are not yet high enough and regulatory certainty is not yet firm enough to effectively discourage the use of coal for electricity generation. The new plants aren’t even being built in a way that can be easily modified to incorporate carbon capture and storage.

One last story is more tangentially related to climate change: tomorrow’s federal election in Australia will partly turn on voters responses to the positions adopted on climate change by the Labor and Conservative candidates, respectively.

In general, I don’t think The Economist takes the problem of climate change seriously enough. They write good-sounding articles in situations where it is the focus, but often miss it completely or mention it only trivially in articles on energy trends, business, or economic growth. That said, their ever-increasing coverage of the issue is probably representative of its ever higher profile in the planning of the world’s most influential people.

Climate sensitivity and stabilization concentrations

The European Union has a widely quoted objective of avoiding anthropogenic temperature rise of more than 2°C. That is to say, all the greenhouse gasses we have pumped into the atmosphere should, at no point, produce enough radiative forcing to increase mean global temperatures more than 2°C above their levels in 1750.

What is less commonly recognized is how ambitious a goal this is. The difficulty of the goal is closely connected to climate sensitivity: the “equilibrium change in global mean surface temperature following a doubling of the atmospheric (equivalent) CO2 concentration.” According to the Intergovernmental Panel on Climate Change, this is: “likely to be in the range 2 to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C. Values substantially higher than 4.5°C cannot be excluded, but agreement of models with observations is not as good for those values.”

Taking their most likely value, 3°C, the implication is that we cannot allow the doubling of global greenhouse gas concentrations. Before the Industrial Revolution, carbon dioxide concentrations were about 280ppm. Today, they are about 380ppm.

Based on the IPCC’s conclusions, stabilizing greenhouse gas levels at 450ppm only produces a 50% chance of staying below 2°C of warming. In order to have a relative high chance of success, levels need to be stabilized below 400ppm. The Stern Review’s economic projections are based around stabilization between 450 and 500ppm. Stabilizing lower could be quite a lot more expensive.

Finally, there is considerable uncertainty about climate sensitivity itself. Largely, this is the consequence of feedback loops within the climate. If feedbacks are so strong that climate sensitivity is greater than 3°C, it is possible that current GHG concentrations are sufficient to breach the 2°C target for total warming. Some people argue that climatic sensitivity is so uncertain that temperature-based targets are useless.

The 2°C target is by no means sufficient to avoid major harmful effects from climate change. Effects listed for that level of warming in the Stern Review include:

Failing crop yields in many developing regions
Rising number of people at risk from hunger, with half the increase in Africa and West Asia
Severe impacts in marginal Sahel region
Significant changes in water availability
Large fraction of ecosystems unable to maintain current form
Rising intensity of storms, forest fires, droughts, flooding, and heat waves
Risk of weakening of natural carbon absorption and possible increasing natural methane releases and weakening of the Atlantic Thermohaline Circulation
Onset of irreversible melting of the Greenland ice sheet

Just above 2°C, there is “possible onset of collapse of part or all of Amazonian rainforest” – the kind of feedback-inducing effect that could produce runaway climate change.

George Monbiot has also commented on this. The head of the International Energy Agency has said that it is too late for the target to be met (PDF).

Weakening carbon sinks

Some recent figures published in the American Proceedings of the National Academy of Sciences suggest that terrestrial and marine carbon sinks are losing their ability to absorb carbon. In 2000, oceans and plant growth collectively absorbed about 600 of every 1000kg of carbon dioxide released into the atmosphere. In 2006, that had fallen to 540kg. While there is some degree of annual variation in such figures, a persistent downward trend would necessitate even more aggressive cuts in global human emissions.

Atmospheric CO2 concentrations are now about 383ppm, and increasing by nearly 2ppm a year, in line with growth in annual emissions of about 3.3%. Total emissions in 2006 were about 9.9 gigatonnes, compared with 8.4 gigatonnes in 2000. Recall that those figures are just for carbon dioxide; other greenhouse gases, such as methane and nitrous oxide, also contribute to planetary warming.

If terrestrial and marine carbon sinks continue to suffer from a reduced capacity to absorb CO2, the total level of sustainable emissions for the planet may end up being even lower than the 5 gigatonnes that the Stern Review estimates the planet can handle.

Trade and greenhouse gas emissions

Countries that are short on land and water import wheat from countries that have lots of both. In a way, you can see this as the small dry country ‘importing’ land and water in the conveniently transportable form of edible grains. The conveyance is an indirect one (you do not pay a ‘water surcharge’ on a bag of flour), but differences in relative factor prices can lead to opportunities for universal gains from trade.

Something similar happens with greenhouse gas emissions, though it takes the form of an externality rather than a priced component of a transaction. When manufacturing or primary commodities takes place in one state and the products of those industries are consumed in another, the total emissions in the exporting countries include some component for which the importing country arguably bears moral responsibility. When a Canadian buys an iPod made from Chinese energy and Sudanese oil, it seems fairest to say that the Canadian is responsible for the associated emissions.

A 2003 OECD study attempted to quantify such transfers using data from 1993 to 1998. For that span of time, the United States effectively imported an average of 263 megatonnes of carbon emissions per year: about 5% of their domestic total. China, by contrast, exported about 360 megatonnes: a figure equivalent to 12% of their GHG production. Canada, with all its forest and hydrocarbon industries, apparently exported about 54 megatonnes: about 11% of our emissions during that period.

Trying to calculate these on an ongoing basis and transfer responsibility from makers to buyers is simply impractical. Thankfully, the establishment of a global price for carbon would achieve the same effect without all the paperwork. It doesn’t matter if the tax is imposed at the point of production or the point of consumption. In the former case, producers would pass the cost to consumers anyhow.

Source: Ahmad, Nadim. “A Framework for Estimating Carbon Dioxide Emissions Embodied in International Trade of Goods.”

Forestry and fossil fuels

One of the most startling distinctions when you look at emissions data from developed and developing states is the relative share of CO2 from fossil fuels and CO2 from land use change and forestry.

In developed countries, 81% of total emissions consist of CO2 produced by the burning of fossil fuels. 19% of emissions are non-CO2 greenhouse gasses, with 11% of that coming from methane and 6% from nitrous oxide. The amount from land use change and forestry barely even registers.

In developing states, by contrast, CO2 from land use change and forestry comprises 33% of total emissions. CO2 from fossil fuels is a more moderate 41%, though it is growing quickly in many countries.

Within the least developed states, land use change and forestry accounts for 62% of total emissions. Largely, this is on account of deforestation. CO2 from fossil fuels produce just 5% of the total.

Part of what this shows is the importance of producing international agreements that take into account the differing emissions profiles of states in different stages of development. Toughening automobile emission standards might make a big difference in Germany, but very little in Chad. By contrast, providing funds to forest rangers in Malaysia or Indonesia might produce big emission reductions.

Source: World Resources Institute. “Navigating the Numbers: Greenhouse Gas Data and International Climate Policy.” 2005.

IPCC 4AR SPM

Yesterday, the Intergovernmental Panel on Climate Change (IPCC) released the Summary for Policymakers (PDF) for the Synthesis Report of the Fourth Assessment Review. That’s what the impenetrable ‘IPCC 4AR SPM’ signifies.

To clarify what that really means, it must be understood that there are a number of levels to the work of the IPCC. Every few years, there is an assessment review meant to evaluate the state of published scientific literature on climate change. The first was in 1990. Subsequent reports have been released in 1995, 2001, and 2007. Each report consists of contributions from three working groups. Each working group writes a report, and each of those reports includes a Summary for Policymakers (SPM). The three working group reports are also combined into a synthesis report, which gets an SPM of its own. That’s what came out yesterday for the Fourth Assessment Review. Each of these reports is negotiated by scientists and approved by the IPCC member states. The SPMs are hashed out by government representatives line by line. That’s what the meeting that just ended in Valencia was about.

The Fourth Assessment Review has examined far more studies than the Third Assessment Review did: 577 compared to 95. Partly on account of that, it marks a big step forward in scientific certainty about the issue. As piles of media coverage stresses, the news isn’t good.

Shipping and invasive species

Globalization has been profoundly associated with massive sea freight shipments. Primary commodities flow from states with rich resource endowments to others with processing facilities. Labour intensive goods are shipped from where labour is cheap to where the goods are demanded. In the process of all this activity, a lot of oceanic species have been able to move into waters they would never otherwise have reached. This unintentional human-induced migration has occurred for two major reasons: the construction of canals and the transport of ballast water. This brief discussion will focus on the latter.

Each year, ships carry 3 – 5 billion tonnes of ballast water internationally. The water is taken on in port, once a ship has been loaded. This is necessary to make the ship balanced and stable at sea. The water taken on can easily include hundreds of marine species of which many of which are capable of surviving the journey. If they get expelled in a suitable environment, these creatures can alter ecosystems and crowd out local species. Sea urchins that have arrived in this way have been extinguishing kelp beds off the west coast of North America, destroying sea otter habitat in the process. Zebra mussels are another infamous example of a problematic invasive species.

Efforts to prevent the transmission of species through ballast water take a number of forms:

Ejecting the water taken on in port in the open ocean: most of the species expelled should die, and the new waters taken on should be relatively free of living things
Poisoning the creatures in the ballast water: this can be done with degradable biocides like peracetic acid and hydrogen peroxide
Transferring ballast water to a treatment facility at the arrival port
De-oxygenating the water in ballast tanks: this kills most species, if the deoxygenated conditions are maintained for long enough

None of these approaches is completely effective. Each retains some possibility of unintentionally introducing invasive species. Several also have other environmentally relevant effects.

That said, simply making an active effort to prevent species transmission between ecosystems marks a big change in human thinking. Not long ago, species were often introduced willy-nilly into entirely new environments: for aesthetic, practical, or whimsical reasons. Infamous cases include those of Eugene Schieffelin – the man who introduced starlings to North America because he wanted to continent to contain all the birds mentioned in the works of Shakespeare – and Thomas Austin – the British landowner who introduced rabbits to Australia because he missed hunting them. Wikipedia has a comprehensive list of such introduced species.