BELEM, Brazil (AP) — Several nations and environmental groups on Friday slammed proposals in the final stages of this year’s U.N. climate talks for failing to explicitly mention the cause of global warming — the burning of fuels such as oil, gas and coal — with one top negotiator warning the talks are on “the verge of collapse.” Juan Carlos Monterrey Gomez, a top negotiator for Panama, said the decades-long United Nations process risks “becoming a clown show” for the omission.