Category: Science

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

Is runaway climate change possible?

One aspect about the possibility of runaway climate change needs to be clarified. The basic mechanism through which it could take place is akin to a feedback loop in a sound system: a small initial warming gets amplified through a feedback, producing more warming in a manner that itself generates even more warming. For such a loop to occur, the feedback effect needs to be quite strong.

Stefan–Boltzmann’s law expresses this mathematically. For an intuitive appreciation, consider the difference between bank lending and a nuclear chain reaction. In an idealized case, a bank would draw from the savings of customers to make a loan. The recipient of that loan might then put part of it in the bank, and the bank may then make additional loans on the basis of that. The total lending of the bank becomes larger than the original loan, but to a non-infinite extent. By contrast, each time an atom of uranium splits in a runaway chain reaction, it releases neutrons that cause more than one other atom to split as well. The result is a reaction occurring at an ever-increasing rate.

It is quite possible that genuine runaway climate change is not possible on Earth – that the existing feedbacks are of the bank lending rather than the nuclear blast variety. That being said, the possibility of warming itself producing further warming remains extremely worrisome. It wouldn’t require ever-escalating temperatures for climate change to be globally devastating. Quite probably, any warming of more than 5˚C would deserve the adjective. The most credible climatic models project approximately that level of warming by 2100, if emissions continue to increase at the present rate.

Mycelium Running

Paul Stamets’ Mycelium Running: How Mushrooms Can Help Save the World is an informative text, written by a true believer. While it contains a lot of practical information, the author’s unbridled enthusiasm sometimes makes you doubt how valid the more fantastic claims are. That being said, it certainly provides some concrete and believable examples of situations where the strategic use of fungi can have beneficial health and environmental effects.

After providing some basic information about the biology of fungi, Stamets covers four different kinds of ‘mycorestoration.’ He shows how patches of mycelium (the tangled, stringy mass that makes up the bulk of fungi) can be used to filter water flowing through – an application that might have particular value downslope from farm animals. The section on mycoforestry shows how mushrooms can accelerate the breakdown of debris from logging, allowing nutrients to return to the soil. It also addresses the ways in which mycorrhizal fungi on the roots of plants can enhance their growth and health. In a section on mycoremediation, Stamets highlights the ability of different fungi to digest or absorb toxic materials ranging from crude oil to nerve gas to radioactive strontium. Finally, a section on mycopesticides describes ways in which insect-attacking fungi can be used to prevent and cure insect infestations.

In addition to the sections outlining the potential of fungi in general, the book includes a lot of practical information about different types of mushrooms, their uses, and how to grow them. It covers different ways of going from spores to a mushroom patch, at scales ranging from a small garden installation to the very large scale. The last hundred pages is a species-by-species catalogue of different mushrooms: how they look, how to grow them, nutritional information, etc. The assertions about mushrooms having intelligence (partly on the basis of mycelium looking like neurons in a brain), I definitely have my doubts about. The step-by-step instructions on producing mushroom patches, I have no doubt could be invaluable to someone wishing to put fungal theory into practice.

Fungi are probably the class of organisms least well understood by most people, and it is rewarding to gain a deeper understanding of the roles they play in ecosystems. More information can be found on Stamets’ website, which also sells various types of mushroom kit and spawn.

Distributed tremor detection

Jesse Lawrence is an Assistant Professor at Stanford University, primarily interested in earthquake seismology and distributed computing. One idea has now merged the two fields: using the accelerometers increasingly commonly built into laptops and phones to make a distributed system for earthquake measurement. By having lots of sensors, it is possible to distinguish earthquakes from other forms of motion. The distributed approach also has advantages: it can provide more detailed information about extreme vibrations than delicate seismometers. It can also provide data collected at many more points, increasing understanding of the earthquake as an effect across a large area. Apparently, with appropriate signal processing, it would be possible to use the system to warn people in surrounding areas not yet affected by the quake, since the data could move more quickly than the seismic waves themselves.

Those wishing to join the Quake-Catcher Network can get the Mac or PC software online. Presumably, people in California are especially encouraged to enroll.

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.