Qu'est-ce que l'effet de serre ?

L'effet de serre est un phénomène naturel qui rend possible la vie sur terre telle qu'elle existe actuellement. En effet, notre atmosphère comprend naturellement des gaz, dits "à effet de serre", qui exercent une action similaire à celle des vitres d'une serre. Ceux-ci laissent ainsi pénétrer une partie de l'énergie solaire mais empêchent la chaleur qu'elle génère de s'échapper, entraînant un réchauffement de la surface de la planète. Sans cet effet de serre, la température moyenne à la surface de la Terre serait en-deçà du point de congélation de l'eau.

Toutefois, les activités humaines, au premier rang desquelles l'utilisation de combustibles fossiles, tels que le pétrole, le gaz et le charbon, ainsi que le déboisement, sont à l'origine d'une augmentation de la concentration atmosphérique en gaz à effet de serre. A titre d'exemple, la concentration atmosphérique en dioxyde de carbone (CO₂) a augmenté de 35% depuis la révolution industrielle pour atteindre un niveau bien supérieur à celui des 650 000 dernières années. Or, l'ajout de gaz à effet de serre dans l'atmosphère, intensifie l'effet de serre, réchauffant ainsi le climat de la Terre. Au total, l'effet de serre est un phénomène naturel, qui connaît actuellement une intensification en raison d'activités humaines, entraînant ainsi un réchauffement climatique.

EU emission caps

The European Union announced a new plan last week to combat global warming that would set firm caps on emissions by 27 countries. Europe first imposed caps on emissions three years ago; this plan toughens them.

Between 2013 and 2020, the E.U. plan would reduce greenhouse gas emissions to 20 percent below 1990 levels. Gone are the national action plans that saw countries adopt schemes that protected local industries. Instead, the European Union would set individual national caps to meet the overall goal. The reduction would be bumped up to 30 percent if the United States and China signed binding climate change agreements.

The plan would correct the faults of the previous cap-and-trade system, which gave away carbon emissions allowances and led to windfall profits for polluters while producing little in reductions. The new proposal would put a price on carbon by auctioning 60 percent of the emissions permits initially and all of them by 2020. There is a mandatory target that 20 percent of E.U. energy be derived from renewable sources, including 10 percent from biofuels. Overall, 60 percent of the European Union's total greenhouse emissions would be covered by the plan.

The E.U. plan is a long way from implementation; the hurdles include approval by the European Parliament. European Commission officials say their new carbon proposals assume a truly global agreement would be in place by the time their new rules take effect in 2013. If not, one option, similar to the proposal pending in Washington, would be to require that competing industries in countries without caps meet emission-reduction targets for goods they export into Europe. That could force them to buy emission credits on the European market -- thus boosting their costs.

But imposing tariffs on imports from countries like China would be fraught with practical problems, including determining how to levy the tariff on a finished product like a car, whose parts are built in multiple countries.

Source: Washington Post, 28/01/08; WSJ, 23/01/08

EU renewable-energy use targets

The European Commission set individual country targets for renewable-energy use, a critical step in an ambitious plan, approved last year, to have 20% of the European Union energy come from renewable sources, such as wind, solar and biofuels, by 2020. The targets could change as the proposal works its way through the EU's legislative system.

According to the Commission is most recent data, only 8.5% of the EU energy consumption in 2005 came from renewable sources. Some of the EU's' biggest countries will have to make substantial leaps thanks to a mechanism that puts a greater burden on countries with higher per capita gross domestic product. Britain-at 1.3% renewable in 2005, according to the Commission's figures-must reach 15%. Germany must go from 5.8% to 18%.

Of particular concern is the extent to which countries should be able to meet their benchmarks by trading renewable certificates instead of investing in renewable energy on their own soil. Under the current proposal countries can stop producers from selling their certificates abroad.

Source: WSJ, 24/01/08