Category: Science

New discoveries, the scientific method, and all matters relating to the scientific study of the physical world

The biomass of humans

Sightline Daily has some interesting numbers up on the relative biomass of human beings, domesticated animals, and wild animals. Apparently, just humans have eight times as much mass as all the wild vertebrates on land. Our mass approximately equals that of all the fish and whales in the ocean. Things are even more dramatic when you factor in domesticated animals. They contain 100 megatonnes of carbon – 20 times as much as there is in all the wild vertebrates on land.

The figures certainly make you think about ecological footprints in a more direct way. They also say something about energy. It seems fair to say that one major factor affecting the total biomass of wild animals is the amount of energy they are able to access. To what extent does our inflated biomass result from unsustainable energy use? Will we be able to maintain it when we can no longer count on ever-increasing production of fossil fuels?

Climate change – rhetoric and urgency

Joseph Romm has written an interesting post on science, rhetoric, and why those who deny the reality of climate change are so effective at spreading their message. Basically, he argues that they are more sophisticated in terms of argumentation styles, and that they are able to engage people on terms they can intuitively appreciate.

Right now, it actually seems more as though the biggest gap is between accepting that humans are causing climate change and accepting what the consequences of that really are. Even organizations that claim to accept the conclusions of the IPCC are nonetheless perpetuating a society emitting grossly unacceptable amounts of greenhouse gasses. How, for instance, can you accept the science of climate change, then deny that it has a major impact on the applicability of a political philosophy based on unending economic growth?

With bluntness very unusual for a scientist, Andrew Weaver summarized the situation we are in:

[U]nless we reach a point where we stop emitting greenhouse gases entirely, 80 per cent of the world’s species will become extinct, and human civilization as we know it will be destroyed, by the end of this century.

We don’t actually need to completely eliminate emissions by the end of the century, but we certainly need to begin cutting them deeply and rapidly. That remains a reality that no government anywhere seems to have fully accepted. Right now, we are like a gambling addict losing $1,000 an hour. If we can get it down to a dramatically lower level, we can keep gambling for longer without going completely bust. Achieving that will require a lot of politically difficult work.

ICCAAT derided, tuna stocks denuded

The International Commission for the Conservation of Atlantic Tunas (ICCAT) has generally shown itself to be ineffective in its mandate. Indeed, some have suggested with a fait bit of validity that the acronym more accurately expands to “International Conspiracy to Catch All Tuna.” A panel including experts from Canada, Japan, and Australia has now published a report with similar conclusions, saying that the organization is “”widely regarded as an international disgrace” and that there have been widespread failures in reducing illegal fishing, providing accurate catch data, and maintaining proper monitoring arrangements. When it appears that even Japan might be willing to back a moratorium on bluefin tuna fishing, you can be sure the situation is dire.

Unfortunately, the global record on fisheries management overall is dismal. Even the Alaskan pollock fishery – considered by many to be one of the most sustainable in the world – has seen a population drop of 50% since last year. The problem is simple to explain and very challenging to solve. There are too many people fishing with gear that is too good. Not enough parts of the sea are set off as safe havens for marine life. Pollution and climate change are also having an impact. Politicians are too spineless to stand up to the fishing lobby, not even in order to defend the public good, but to stop that very industry from destroying itself in our lifetimes. The industry needs to be much smaller and much more tightly regulated; the most destructive gear needs to be banned; monitoring needs to be improved; and states must prove themselves willing to enforce the law.

The chances of all that happening are fairly slim. All told, global fisheries provide one of the most acute examples of where human beings are weighing so heavily on the planet’s physical and biological systems that collapse is rapidly approaching.

Prior related posts:

The Shifting Baselines blog is also an excellent source of fishery-related news.

Snails and ‘love darts’

The oddest thing I learned from Wikipedia recently is that when snails mate, they attempt to shoot one another in the head with a calcium ‘love dart.’ Snails are hermaphroditic, exchanging sperm with one another and later using it to fertilize their own eggs. In Helix aspersa, the darts are coated with chemicals that cause the ducts in the other snail to contract, possibly suppressing the function of sperm-digesting enzymes.

The whole process sounds rather perilous:

The darting can sometimes be so forceful that the dart ends up buried in the internal organs. Sometimes the darts pierce the body or head entirely, and protrude on the other side…

The dart is shot with some variation in force, and with considerable inaccuracy, such that one-third of the darts that are fired in Helix aspersa either fail to penetrate the skin, or miss the target altogether.

A photo accompanying the article shows edible snails (Helix pomatia) engaging in weird but surprisingly photogenic mollusc courtship.

Carbon capture research

Researchers at the University of Calgary say they have a machine that can extract carbon dioxide from the air at a reasonable cost and using relatively little energy. From what I can tell, the CO2 extracted would still need to be buried somewhere. Even so, if such technologies prove cost effective and scalable, they could potentially play a role in stabilizing climate.

More details are in this PDF. Apparently, the tower can capture 15 tonnes per year of CO2 per square metre and each tonne of capture requires 81 kilowatt-hours of electricity (about $4 worth). Estimated total costs per tonne (including capital) range between $12.80 and $43.80.

The Met Office on the urgency of emission reductions

The Met Office is the official national weather service of the United Kingdom, subsidiary to the Ministry of Defence. Their website provides a wealth of information about climate change. For instance, they have projections based on in-house models, a PDF containing “the known facts about climate change.” One page on the site lists the six key facts about the issue of global warming:

  1. Climate change is happening and humans are contributing to it
  2. Temperatures are continuing to rise
  3. The current climate change is not just part of a natural cycle
  4. Recent warming cannot be explained by the Sun or natural factors alone
  5. If we continue emitting greenhouse gases this warming will continue and delaying action will make the problem more difficult to fix
  6. Climate models predict the main features of future climate

It is very refreshing to see this kind of thing from an authoritative source: providing comprehensible information on the strength of the scientific consensus. The head of the Met Office recently published an article in The Guardian stressing the urgent need to cut greenhouse gas emissions:

Even with large and early cuts in emissions, these projections indicate that temperatures are likely to rise to around 2C above pre-industrial levels by the end of the century. If action is delayed or is slow, then there is a significant risk of much larger increases in temperature. The uncertainties in the science mean that even if the most likely temperature rise is kept within reasonable limits, we cannot rule out the possibility of much larger increases. Adaptation strategies are therefore needed to deal with these less likely, but still real, possibilities…

Even if emissions start to decrease in the next two years and reach a rapid and sustained rate of decline of 3% per year, temperatures are likely to rise to 1.7C above pre-industrial levels by 2050 and to around 2C by 2100. This is because carbon dioxide already in the atmosphere will be around for many years to come and the climate takes some time to respond to these changes. Only an early and rapid decline in emissions gets anywhere close to the target of 50% reduction in emissions by 2050 put forward by the G8.

Contrast that with a world where no action is taken to curb global warming. Then, temperatures could rise as high as 7C above pre-industrial values by the end of the century. This would lead to significant risks of severe and irreversible impacts.

Clear, scientifically-informed, and forcefully expressed – we would be lucky to see climate change discussed in such a manner in some of the developed and developing nations less progressive on the issue than the United Kingdom has generally shown itself to be.

North/South historical versus future emissions

It is common to hear officials from developed states say things akin to this: “Yes, we are the ones who have historically done the most to create climate change – but we will be eclipsed by developing nations in the future.” While probably valid to some extent, there are many possible responses to this. There are arguments about who got rich how, as well as whose current per-capita emissions are high or low. What I am objecting to here is the curious methodology sometimes used to describe the developed/developing past/future dynamic.

Sometimes, states say both (a) developed states will continue to increase their emissions, in line with how they have been rising recently and (b) we will cut our emissions, according to our existing plan. If you step beyond that to compare your target future numbers with your business-as-usual projections for developing states, you make them look like a huge problem by comparison. One problem with this is that it is akin to saying the following: “I know I have been a problem gambler, but I have a plan to cut it down. I am going to halve my annual gambling losses in three years, and eliminate 80% of them in five. My buddy here, however, is a really compulsive gambler. He keeps losing more and more at an increasing rate. As such, his projected future losses are huge. Indeed, the amount I have lost so far is tiny compared to the amount he is going to lose in the future.” It is paradoxical because you are using the assertion that you will do better in the future to avoid present demands that you do more to reduce future emissions.

You are basically assuming that you can and will change, while others will not. No rich country government that has adopted targets for cutting emissions claims that cutting emissions requires cutting GDP. Nobody in power is touting a “stop climate change through recession” approach. As such, they must believe it possible to maintain economic growth while cutting emissions. While that may or may not be a valid assumption over various spans of time, it is an assumption that must be applied to developing states as well as developed ones.

In short, both developed and developing states need to cut emissions. The large probable future emissions from states like India and China are relevant to climate planning, partly insofar as concern about them could prompt useful transfers of wealth and low-carbon technology towards those states. At the same time, the wealth of the developed world – and the historical emissions that helped generate it – are also highly relevant. So too are the much larger non-climatic challenges being faced in the developing world. The developed world needs to start taking the kinds of steps necessary for actually hitting their 2020 and 2050 targets, in the process demonstrating to developing states how the transition can be accomplished in a politically acceptable way.

Parallels between AIDS and climate change

New research suggests that the AIDS virus first emerged in human populations about 100 years ago. That seems a bit surprising, given the way in which the impacts have exploded in the last few decades. The explanation is simply to consider the lag times and exponential growth curves involved. In 2007, 2.1 million people died of AIDS, from among the 33.2 who were infected. Despite improved access to antiretroviral therapies, the sheer extent to which the disease has spread means that the deaths in any recent year probably far exceed the combined deaths from the first few decades of the disease’s existence.

Disturbing parallels exist in relation to climate change. Once again, there is a lag between the cause (contracting HIV or emitting greenhouse gases) and the effects (destruction of the immune system or climatic change). Once again, the rate of growth in the underlying cause has been exponential. Thankfully, there is reason to hope that we are still not too far along the path, when it comes to climate change. It is like having discovered AIDS decades before we actually did – it would have allowed more time to develop and deploy treatments and encourage changed behaviours. It would also have made the peak in number of infections lower and sooner to arrive, before crossing over to the long and difficult slide towards elimination.

Geoengineering with lasers

This Economist article on geoengineering takes the same basic stance I have: that it is worth developing as a backup strategy, but that it is too dangerous to rely upon as an alternative to mitigation. That being said, they treat some of the options more generously than I would. On the basis of what I have read so far, ocean fertilization seems unlikely to work, and the secondary side-effects of sulfate injection seem too severe – not to mention how any geoengineering strategy that does not actually reduce carbon dioxide concentrations dooms to oceans to becoming ever-more-acidic for as long as we keep burning fossil fuels.

The strangest idea discussed in the article sounds like the kind of approach a Bond-villain would dream up:

Perhaps the most intriguing idea—which was published last year, though not discussed by the Royal Society—is to eject carbon dioxide from the atmosphere at the Earth’s poles, using the planet’s magnetic field. This may sound absurd, but oxygen already leaks out this way (the phenomenon is the subject of a paper just published by Hans Nilsson of Swedish Institute of Space Physics). Alfred Wong, a researcher at the University of California, Los Angeles, proposes that a system involving powerful lasers and finely tuned radio waves could encourage carbon dioxide to take the same route. His calculations suggested that using lasers to ionise molecules of carbon dioxide, and radio waves to get them to spin at the correct rate, would cause those molecules to spiral away from Earth along the lines of magnetic force until they were lost for ever in space.

I have no idea whether this could actually work. Furthermore, implementing it meaningfully would require ejecting about 35 billion tonnes of carbon dioxide per year into space. That seems likely to have some weird consequences.