This interactive guide explains the crucial points of the agreement and their effect on the planet.
After two weeks of final negotiations in the French capital, 196 nations have come to a new agreement on climate change. In setting ambitious new targets for limiting global warming, it has been called a "historic turning point" that "paves the way to the end of fossil fuels" - although not everyone is embracing the pact. Here is a very brief guide to some of the key elements of the Paris Agreement, and a reminder of some of the reasons so many are so keen to prevent warming from increasing any further.
1.5 or 2 degree C goal
The agreement calls for the world's nations to take steps to limit total warming worldwide to less than 2 degrees C, and to work toward limiting it to 1.5 degrees C. Given that warming is already at 1 degree C, it's almost certainly a promise that will not come close to being kept. That 1.5 degree goal, for example would, according to one estimate, require fossil fuel emissions in developed countries to virtually stop by around 2030. However, some advocates argue that the very act of acknowledging such an ambitious goal in an international agreement is a powerful statement.
All must contribute, rich and developing countries
In contrast to previous "top-down" agreements, the Paris negotiations involved a "bottom-up" process, in which every country submitted its own aspirational goal for reducing greenhouse gas emissions, called an Intended Nationally Determined Contribution (INDC). The agreement states that all NDCs must represent a progression over time. Still, the agreement acknowledges the need for different speeds: developed countries are urged to adopt "economy-wide absolute emissions reduction targets," while poorer nations are encouraged to "move to" such reduction or limitation targets "over time."
Set goals for 2018, 2020 and beyond
The agreement comes into force in 2020, but requires action to be taken before then, and improvements to be made thereafter. Commitments presently made will not only fail to limit warming to 1.5C, say some, but set the world on course for 3C of warming. So in 2018, there will be an interim review of pledges; then, beginning in 2023, there will be five-year reviews at which countries will take stock of their emissions reduction commitments and make additional, progressively more ambitious pledges.
Contributions from richer countries $100 billion/year
The agreement places a legal obligation on richer nations to provide financing to developing countries for climate and adaptation and mitigation efforts. It also encourages other countries to provide financial support voluntarily. The floor for such financial assistance has been set at $100 billion per year, with an agreement that, before 2025, countries should agree a "new collective, quantified goal."
Reducing use of fossil fuel
The text doesn't actually mention fossil fuels, the source of all this trouble, but does address their pollutants. There is a general commitment for greenhouse gas emissions to peak "as soon as possible" and to achieve "balance" between emissions and sinks in the second half of the century. This is of course where the rubber meets the road: as George Monbiot notes, "Until governments undertake to keep fossil fuels in the ground, they will continue to undermine the agreement they have just made."
There’s no mention in the final text of the aviation and shipping industries, which by 2050 could account for 39 percent of global emissions. Groups that were pushing for explicit reference to decarbonization instead have to make do with a goal to “achieve a balance between anthropogenic emissions ... and removals by sinks ... in the second half of this century.” Some had pushed for liability and compensation for those losing their homes and livelihoods to climate change. Says Bill McKibben: “This … won’t save the planet. It may have saved the chance to save the planet.”
It may be too late to stop or reverse some changes. For example, the West Antarctic Ice Sheet appears to be in the early stages of an unstoppable collapse -- which would add enormously to future sea level rise. Melting sea ice, on the other hand, does not affect sea levels, but its disappearance does imperil Arctic species such as polar bears. But, unlike the glacial ice of the West Antarctic Ice Sheet, Arctic sea ice declines -- modeled at about 15 percent per degree of warming -- can be halted and reversed, according to a 2010 study.
The ongoing California drought has been intensified by 15 to 20 percent by climate change, a study published in August argued. Heat waves are, naturally, expected to last longer, occur more frequently and be more extreme in a warming world. The combination of drought and other extreme weather events is likely to take its toll on agriculture: The U.S. Corn Belt is projected to experience a loss of 11 percent corn production per degree of warming, while at the same time global cereal demand is expected to rise by roughly 1.2 percent per year.
Although tropical cyclones are expected to decline in frequency, the intensity of those that do form is predicted to increase by 1-4 percent per 1 degree C of warming, while the total destructive power increases by 3 to 12 percent. Extreme rain events are likely to intensify by 5-10 percent for every degree of warming. Across northern mid-latitudes, the kind of extremely hot summers one might experience every 20 years could instead be expected every two to 10 years in a world that is 2 degrees warmer than pre-industrial revolution levels.
The average area burned by wildfire in parts of the United States is expected to increase by two to four times per degree of warming. In general, areas that are already fire prone, such as the evergreen forests of the western United States and Canada, should become even more vulnerable with increased warming. Conversely, some grasslands and shrublands could wither into deserts, decreasing their fire risk, but only at the expense of losing existing ecosystems.
Sea Level Rise
There’s a big reason that low-lying Pacific Island states were among the most determined to push for an aggressive deal in Paris: They're among those in most immediate danger. Sea levels are already rising -- by about 7.5 inches since 1870 in fact -- with a large fraction of that caused by thermal expansion of the ocean. By 2100, at present rates of warming, that figure could be 20-39 inches, or even more if there's catastrophic melting of the Greenland or Antarctic ice sheets.