The Lima climate talks will produce more than 50,000 metric tons of carbon dioxide, a record carbon footprint for any U.N. climate meeting measured, organizers say — though all that greenhouse gas pollution will be offset by host country Peru's protection of forest, organizers say.

One big reason for that footprint, about 1.5 times the norm: The venue was built from scratch. Eleven football fields of temporary structures arose for the 13-day negotiations from what was an empty field behind army headquarters. Also, unreliable sunshine in Lima is one reason solar panels weren’t used. And organizers say technical difficulties meant they couldn’t draw power from Peru’s grid, which is about 52 percent fed by non-polluting hydroelectric power. So diesel generators are being used for electricity. Big ticket items in the footprint include: construction, nearly 20 percent; jet fuel burned by 11,000 delegates and observers, 30 percent; local transportation (organizers hired more than 300 buses), 15-20 percent. Also, the 580 square miles (1,500 square kilometers) of forest must lie unperturbed for a half-century to neutralize all that carbon.

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#UPDATE: 'Still a chance' to limit global temperature rise to 2C, UN's Ban says at Lima talks http://t.co/eoFTZhjgA2 — Agence France-Presse (@AFP) December 9, 2014

#COP20 update: Today begins the high-level, politically contentious segment of the UN Climate Talks in Lima... — WWF News (@WWFnews) December 9, 2014

— The Associated Press