快猫短视频

SMALL print in the Kyoto Protocol threatens to make global warming more
severe than it need be over the next 10 years or so. An obscure rule is
discouraging countries from applying cheap technologies that could dramatically
curb global warming in the short term, warns a British climate scientist.

Measures as simple as fixing leaky gas pipes or capping landfill sites could
cut emissions of methane, a powerful and fast-acting greenhouse gas, says Euan
Nisbet of Royal Holloway, University of London. But the protocol鈥檚 rules mean
nations will get little reward for such work, compared to the often more
expensive efforts to cut carbon dioxide. 鈥淐utting CO₂ emissions is
essential,鈥� he says. 鈥淏ut we have neglected methane and the near-term benefits
it could bring.鈥�

The Kyoto Protocol, finalised in Marrakech in November, covers six greenhouse
gases released by human activity, including CO₂, methane, nitrous oxide
and hydrofluorocarbons. Each gas has a different warming potency and a different
lifetime in the atmosphere. Under the protocol, a 鈥渉undred-year rule鈥� is used to
calculate their effect on greenhouse warming: that is, the protocol tots up
their warming potential over 100 years.

This increases the emphasis on carbon dioxide, which stays in the atmosphere
for about a century, and downgrades the significance of methane. Methane is the
second most important greenhouse gas, but it largely disappears after about a
decade.

Releasing 10 kilograms of methane into the air today will warm the world
about as much over the next decade as a tonne of CO₂. But because so
much of the gas disappears, its warming potency over 100 years is only a fifth
that of CO₂. It鈥檚 the latter figure that has been used to draw up Kyoto
emissions targets.

The effect of the hundred-year rule, Nisbet told a climate conference at
Green College, Oxford, last week, is to give a low priority to cutting methane
emissions, even though such efforts are often cheaper and would certainly have a
bigger short-term impact.

His warning comes at a time of growing concern about the short-term impact of
climate change. Climatologists such as Richard Alley of Penn State University
fear that the more the climate is forced to change, the more likely it is to hit
some unforeseen threshold that can trigger sudden changes in weather patterns
(快猫短视频, 2 February, p 18).

Some climate scientists are reluctant to raise the issue of methane, as they
fear it will give ammunition to opponents of the Kyoto Protocol. But others are
backing Nisbet鈥檚 call. 鈥淚t makes a lot of sense to try to reduce non-CO₂
gases such as methane because, in some ways, it鈥檚 easier,鈥� says Jim
Hansen of NASA Goddard Institute for Space Studies, one of the first scientists
to call for global action on the greenhouse effect.

Nisbet thinks the Kyoto rules should be changed. 鈥淎doption of a 20-year time
horizon would substantially increase incentives for reducing methane,鈥� he told
the meeting. Analysts say it is probably too late to 鈥渕ove the goalposts鈥� for
the first Kyoto target date of 2010. But it will make sense to do it for the
next date, 2015.

Countries such as Britain that have promised to go beyond their formal target
should be encouraged to make extra efforts to tackle methane, says Nisbet. Over
the next 20 years, methane emissions from rotting organic matter in British
landfill sites are likely to cause as much warming as half of all the country鈥檚
transport emissions, he calculates.

He also believes that a greenhouse policy built around cost-effective methods
of methane control, such as plugging leaks in gas pipes, could prove attractive
to the US government, which has set its face against the Kyoto Protocol,
claiming it will damage its economy.

Curbing methane emissions is often cheap and easy, a matter of simply fixing
pipes and putting more soil or inert waste on landfills to encourage the growth
of methane-eating bacteria, says Nisbet. Yet, in Britain at least, regulations
are stacked against such developments. For instance, the financial rules of the
gas industry regulators discourage plugging leaks, and environmental taxes
penalise the dumping of inert waste on landfills.

Changing international rules to tackle methane could put pressure on
developing countries, which would inevitably have to do more to cut their large
emissions from tropical deforestation and draining wetlands. But the overall
effect would be worth it, says Nisbet. 鈥淚 was brought up in a developing
country. I know well that they are much more vulnerable to climate change today.
They want protection now. They are not prepared to think 100 years ahead, which
is what, in effect, the Kyoto Protocol does.鈥�