Tackling climate change calls for global teamwork, but some countries have been less-than-perfect partners.

In order to understand why some nations fall behind in their international climate duties, and colleagues at the Swiss Federal Institute of Technology in Zurich, created a Climate Cooperation Index.

They plan to use it to study what drives a government to cooperate with international climate policy – for instance, if different political systems, poverty, or the expected cost of climate change adaptation make a country a better or worse team player.

They have preliminary results suggesting that countries that have experienced an increase in the variability of their climate are better at cooperating.

Team players

The index is based on five factors: how quickly each country ratified the (UNFCCC) and the Kyoto protocol, how often it paid its contributions to the UNFCCC, whether the country submitted its last emissions report in time, and how much it reduced its CO₂ emissions relative to per capita GDP.

Among major climate players, the UK and Germany came out on top, while the US and Australia – notoriously reluctant to implement global warming policies – ranked low.

Overall, however, these countries appear somewhat middle-of-the-road. At the top of the 188 country list are Latvia, Micronesia and Slovakia – nations which have both cut their emissions and been diligent with their paperwork. The least cooperative countries are Iraq, Brunei, Andorra and Somalia, which have not ratified climate agreements and also flunked out other categories.

of Keele University in the UK says Bättig’s approach is innovative and could be used in international negotiations. Most of the findings in the study confirm what experts would have guessed, he says, except for one counterintuitive finding: countries who are expected to bear the highest costs in reducing emissions were often the quickest to ratify the Kyoto protocol.

Whether this indicates national commitment to the climate cause, however, remains to be seen. “As always in studies like this, the problem is what you are measuring,” says Vogler. “Ratification procedures differ quite widely between different regimes.”

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Recently, the orthodox explanation – that they favour their own genes indirectly by helping their kin – has been fiercely challenged by Edward O Wilson, one of the most prominent evolutionary biologists of our time.

But now a research team led by , of Leeds University, UK, claims to have falsified Wilson’s predictions, showing that genetic relatedness is really the key.

At the core of the dispute is the theory of kin selection, formalised in the 1960s by William Hamilton, accepted by the vast majority of modern biologists and defended by Richard Dawkins. According to Hamilton’s rule, apparent acts of altruism – foregoing reproduction to help others, say – are actually self-serving, because they benefit the altruist’s genes.

Wilson broke with this view, proposing that altruism evolved because it benefits groups, rather than genes. For such “group selection” to take place, he argued, animals don’t need to be closely related, they only need to stick together and cooperate.

Multiple males

He argues that this is more likely to occur when individuals tend to remain in the nest they are born from. So the high relatedness observed in ants, bees and wasps – so-called eusocial species that have a queen and sterile workers – is a consequence, not a cause, of altruism.

If Wilson is right, then there should be no correlation between the degree of genetic relatedness within insect colonies and the level of social cooperation they show.

To test this, Hughes and colleagues looked at a behaviour that has fundamental consequences for colony kin structure – polyandry, which occurs when females mate with more than one male. This enhances female fitness by producing more variable offspring and is a common behaviour throughout the animal kingdom.

“Birds, reptiles, flies, butterflies, beetles – pretty much all species that have been looked at show some level of polyandry,” says Hughes.

Ancestral monandry

Hughes and colleagues looked at the levels of polyandry in 267 species of eusocial ants, bees and wasps. The last common ancestor of these insects was solitary, and eusociality evolved independently on eight different occasions. By looking at how the species are related to each other over evolutionary time, the team could reconstruct the ancestral condition – monandry or polyandry – in each case.

The team found the ancestral condition was invariably monandry. And the same applies to termites, shrimps, ambrosia beetles and most other eusocial organisms.

“[In species excluding ants, bees and wasps] the data is much more limited, but it points in the same direction,” says Hughes. “You always have ancestral monandry when eusociality evolves.” In other words, close genetic relatedness is crucial to the evolution of altruism.

Eventually, once eusociality is evolved and established, insect queens start reaping the benefits of multiple mating, which has evolved several times as a secondary condition, says Hughes.

‘Cut and dry’

Intriguingly, very high levels of polyandry are only observed in species where helpers have entirely lost the ability to reproduce, becoming permanently sterile castes. Again, this is exactly what kin-selection theory predicts, because only when eusociality has become irreversible, and workers have no other option but to help, can the leash of genetic relatedness loosen.

Hughes contents that these results would seem to settle the longstanding debate revived by Wilson.

“Wilson predicted that high relatedness evolves after eusociality. We show that it is ancestral. It’s pretty cut and dry, really,” says Hughes.

Wilson, however, does not agree that the debate has been resolved so cleanly.

“Hughes and colleagues did not prove the correlation of eusociality and ancestral monogamy, because they have no data on the many lines that did not evolve eusociality,” he says.

“And they failed to mention other published explanations of multiple insemination in the later stages of eusociality. The weight of evidence favors the new explanation of close kinship as a consequence of eusociality, as laid out in my BioScience article.”

Hughes accepts that there is much more to altruism than simple genetic benefits.

“It is good to be challenged about our hypotheses,” says Hughes, “Hamiton’s equations have three components in them but we have become very focused on relatedness. [Wilson] has done us a service in drawing attention back to ecological benefits and other components.”

Journal reference: (DOI: 10.1126/science.1156108)

Microbes can survive trapped inside ice crystals, under 3 kilometres of snow, for more than 100,000 years, a new study suggests. The study bolsters the case that life may exist on distant, icy worlds in our own solar system.

Living bacteria have been found in ice cores sampled at depths of 4 kilometres in Antarctica, though some scientists have argued that those microbes were contaminants from the drilling and testing of the samples in labs. And in 2005, researchers revived a bacterium that sat dormant in a frozen pond in Alaska for 32,000 years (see Ice age bacteria brought back to life).

Now, physicist Buford Price and graduate student Robert Rohde, both at University of California in Berkeley, US, have found a mechanism to explain how microbes could survive such extreme conditions.

They say a tiny film of liquid water forms spontaneously around the microbe. Oxygen, hydrogen, methane and many other gases will then diffuse to this film from air bubbles nearby, providing the microbe with sufficient food to survive.

Thus, virtually any microbe can remain alive in solid ice, resisting temperatures down to -55° Celsius and pressures of 300 atmospheres.

Under such harsh conditions, the microbes would not be able to grow and reproduce, but they would still be able to repair any molecular damage, keeping themselves viable for more than a thousand centuries, the team says. “It is not life as we generally think about it,” says Rohde. “[They] are just sitting there surviving, hoping that the ice will melt.”

To test their hypothesis, the researchers studied ice samples taken at various depths in the Antarctic and Greenland ice sheets. They detected isolated microbes that they say must be trapped inside ice crystals.

Survival strategy

Price says the new work may bolster the case for life on Mars. Methane breaks down relatively quickly when exposed to sunlight, so when it was discovered in the Martian atmosphere in 2004, some scientists suggested that methane-producing microbes, or methanogens, might be continually producing more of the gas.

“One possible explanation for the heterogeneous distribution of methane in the Mars atmosphere would be surviving sub-surface methanogens,” Price told New �Ӱ�ԭ��, adding that he and colleagues had previously found methanogens buried under kilometres of ice in Greenland.

Astrobiologist Dirk Schulze-Makuch of Washington State University in Pullman, US, says he doubts that any such microbes could produce enough methane to explain the detections on Mars.

But he says the diffusion mechanism identified in the new work does boost the chances for extraterrestrial life. “The main reason for this is that most of the planets and moons in our solar system are icy worlds,” he told New �Ӱ�ԭ��. “Thus any type of survival mechanism and possible avenue for metabolism in cold and very cold environments would be a great evolutionary trait for any organism on an icy world.”

John Priscu of Montana State University in Bozeman, US, agrees. “We have another mechanism of life support in an environment that would otherwise seem to be inhospitable,” he told New �Ӱ�ԭ��.

Astrobiology – learn more in our out-of-this-world .

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