Talking about cutting carbon emissions sure puts out a lot of carbon.
That's the irony of drawing in 40,000 people, including heads of state, negotiators, activists and journalists, to Paris to hash out what's hoped will be a ground-breaking international agreement to put a brake on global warming.
The last such conference, the so-called COP20 in Lima, Peru, in2014, had a "carbon footprint" of an estimated 50,000 metric tons of carbon dioxide, the biggest carbon footprint of any U.N. climate meeting measured to date. That's more than eight times as much carbon as the 2009 Copenhagen talks and twice that of the 2010 conference in Cancun, Mexico, according to the U.N.
Organizers of the Paris conference, which runs until Dec. 11, say they'll limit COP21's carbon footprint to 21,000 tons of CO2 — but their calculation doesn't take into account transport — and with participants coming from around the world, this is the single biggest contributor to the conference's carbon emissions.
The Paris conference will also be many times larger than Lima was, with 40,000 attendees forecast vs 11,000 in Lima.
However large Paris' carbon footprint is, it will presumably be dwarfed by the reduction in carbon emissions that the leaders hope to sign. But the sight of massive convoys of black SUVs ferrying leaders to give speeches about how much they care about stopping global warming will be a symbol Paris' organizers could live without.
To counter this and ensure that COP21 is "carbon neutral," organizers are taking a variety of measures to offset the conference's emissions.
Among these is the construction of a 2,000-seat assembly hall made from wood from sustainably managed forests. After the conference the assembly hall can be dismantled and reused. Catering has been outsourced to two companies that guarantee to abide by sustainability guidelines, offering locally sourced, organic and non-genetically modified fruits and vegetables.
In addition, hotelier AccorHotels says it will plant trees to offset the emissions represented by every hotel night in the Paris region during the two-week conference, not only for its own hotels but also competitors.
Many of the flights to Paris scheduled during the conference would have happened anyway, so it's hard to separate out how much of those air transport emissions are because of the conference.
Kornelis Blok of Ecofys, a consultancy in renewable energy and carbon efficiency, estimates that emissions related to air transport could reach 40,000 additional tons of CO2. That's based on estimates that each participant travels an average of 10,000 kilometers round-trip. To put that number in perspective, the total emissions of CO2 for The Netherlands are about 200 megatons per year, Blok said.
At Lima an attempt was made to encourage conference attendees to come by bicycle. At the insistence of Peru's environment minister a bicycle parking lot was built on site, but only about 40 people used it daily. The COP21 site, at an airfield about 8 miles from central Paris, can be reached by bicycle in under an hour — about the same time it takes to get to the same site by car or public transport during the biennial Paris Air Show.
A bike rack with places for 50 bicycles is set up a short walk from the COP21 main gate. On day 2 of the conference, just three bikes were locked there.