Delegates from 190 nations are gathering in Poznan, Poland to launch the latest round of global warming negotiations. Formally called the 14th Conference of the Parties (COP-14) to the United Nations Framework Convention on Climate Change (UNFCCC), the climate negotiators face three huge challenges to completing a new international treaty to replace the Kyoto Protocol, which is set to expire in 2012. First, the Kyoto Protocol itself is failing to cut the emissions of greenhouse gases. Second, a world entangled in a global economic meltdown will not readily accept the higher energy prices that will follow from cutting greenhouse gases. And third, new scientific evidence has raised questions about future climatic trends and the predictive accuracy of climate models.

Kyoto Protocol Problems

Nations that signed the Kyoto Protocol agreed to cut their emissions of greenhouse gases—chiefly carbon dioxide—by an average of 5 percent below the level they emitted in 1990. In one sense, the collapse of the former Soviet Bloc economies has already helped achieve this goal. On the other hand, most economically developed nations—including many countries in Western Europe, as well as Japan, Canada, and Australia—are not meeting their Kyoto Protocol goals. In November, the United Nations issued Greenhouse Gas Data, 2006, which reported that for the 41 signatories to the UNFCCC, greenhouse gas emissions in 2004 were 3.3 percent below the 1990 level. However, as the report notes, the overall decrease is composed of a 36.8 percent decrease among former Soviet Bloc countries and an 11 percent increase among the remaining industrialized countries.

When one looks at the results for the signatories to the Kyoto Protocol, they look somewhat better, with 2004's greenhouse gas emissions 15.3 percent below 1990's level. That sounds like a lot of progress has been made. But is that correct? Not exactly. Again, this level of cuts was achieved because of the economic collapse of the Soviet Bloc. Between 1990 and 2004, emissions from former Soviet Bloc signatories fell 37 percent while rising by 3.7 percent among other industrialized signatories to the Kyoto Protocol.

While emissions between 1990 and 2004 fell in Germany (17 percent, largely because of the close of East Germany's moribund industries) and the U.K. (14 percent, largely due to the country's substituting natural gas for coal in electricity generation), they rose in most of the other large industrialized economies. For example, between 1990 and 2004, Canada's emissions increased 27 percent, Australia's 25 percent, Japan's 6.5 percent, Italy's 12 percent, Turkey's 72 percent, Spain's 49 percent, and the United States' 16 percent. As the U.N. report drily notes, "In general, the message from the 2006 data is that industrialized countries will need to intensify their efforts to reduce greenhouse gas emissions." Indeed.

Financial Meltdown Meets Climate Meltdown

Rationing carbon dioxide emissions means higher energy prices for producers and consumers. For example, the European Trading Scheme (ETS) was set up to issue and trade permits to emit carbon dioxide. The scheme covers about 11,000 factories and plants that are responsible for 45 percent of the European Union's greenhouse gas emissions. Under the scheme countries cap annual greenhouse gas emissions and issue permits to cover those emissions. If a company exceeds its allowance, it must buy permits from other companies that have extra permits. Since 2005, when the ETS was established, permit prices have been very volatile, rising as high as $40 per metric ton earlier this year. This past month, permit prices fell to $19 per ton. The global economic contraction means that there will be less demand for energy intensive goods such as cars and steel which, in turn, means that there will be less demand for offsetting emissions permits.

Many environmental activists now worry that falling carbon permit prices means that companies will not invest in low-carbon energy technologies such as windmills or solar panels. In fact, the global credit crunch has already led to the cancellation of some projects.

At the Poznan Climate Change Conference, negotiators are aiming for a new post-2012 climate change treaty that will ensure that concentrations of greenhouse gases do not rise above 450 part per million (ppm) in the atmosphere. That's the threshold at which many climate models suggest temperatures will increase to about 2 degrees Celsius above pre-industrial levels. However, researchers such as NASA's James Hansen believe 350 ppm is too high (we're already at 385 ppm). A new study by researchers associated with Britain's Tyndall Centre for Climate Change Research concludes that, "it is increasingly unlikely any global agreement will deliver the radical reversal in emission trends required for stabilization at 450 ppm carbon dioxide equivalent." That holds true for 550 ppm or even 650 ppm. The study soberingly adds, "Unless economic growth can be reconciled with unprecedented rates of decarbonization (in excess of 6% per year), it is difficult to envisage anything other than a planned economic recession being compatible with stabilization at or below 650 ppm carbon dioxide equivalent." That's not a message that politicians will be able to sell their citizens.

Climate Conundrums

Given that climate is by definition a long-term phenomenon, one should be cautious about interpreting ten years of data. Still, it is the case that global average temperatures have remained essentially flat since 2001 while the level of carbon dioxide in the atmosphere has increased by about 5 percent. It is also true that this decade is on average warmer than the previous decade, though so far there is no clear upward trend. And what about the future? Earlier this year, a German climate modeling group published a study in Nature suggesting that global average temperatures may not increase in the coming decade because of offsetting natural climate variations. Policymakers will likely find it difficult to persuade the public to endure the economic pain of higher energy bills if temperatures are not actually increasing.

Clearly, most climate modelers believe that adding more carbon dioxide will eventually lead to unacceptably high global temperatures. However, other researchers question aspects of those models. For example, are the models' estimates of the amount of carbon dioxide that's likely to be emitted from soils too high? Are cloud feedback estimates biased in a positive direction, leading researchers to predict greater warming than is likely to occur? And is soot responsible for most of the recent warming in the arctic?

All that stands in the way of a grand new climate treaty, in other words, is a failing climate treaty, a massive global financial crisis, and a number of remaining climatic uncertainties. Those may be enough.

Ronald Bailey is reason's science correspondent. His book Liberation Biology: The Scientific and Moral Case for the Biotech Revolution is now available from Prometheus Books.