oslo backers global accord fight climate change formally come force friday say confident deal survive legal challenge u.s. republican candidate donald trump win next week presidential election trump threaten reject accord negotiate nearly 200 governments include u.s. president barack obama trump tweet global warm concept invent chinese harm u.s. industry contrast democratic rival hillary clinton strongly support plan enter force major greenhouse gas emitters unite state china india ratify paris agreement aim phase man-made greenhouse gas second half century avert flood heatwaves droughts rise sea level delegate signatory nations meet moroccan city marrakesh nov. 7-18 start turn many promise tackle climate change action draw rule book sometimes fuzzily word accord reach last december add urgency 2016 set hot year since record begin 19th century u.s. election nov. inject large dose political uncertainty gather environment minister senior officials marrakesh relatively speedy ratification climate pact year many predictions partly drive trump threats reject accord delegate play risk president trump renege deal momentum would take heck climate skeptic back pedal say tosi mpanu mpanu democratic republic congo head group 48 least develop countries morocco negotiations really strong mobilization ratify trump win think change anything moroccan environment minister hakima el haite host marrakesh meet say expect trump elect would challenge agreement say american people generally supportive climate action businessman trump understand climate change opportunity create job new technologies tell reuters recently new york entry force give protection paris agreement international law article 28 say government want quit wait four years formalities length u.s. presidential term win trump likely focus efforts domestically undo obama plan cut u.s. emissions coal-fired power plant paris agreement also help unlock u.n. accord year limit emissions airlines powerful greenhouse gas use air conditioners refrigerators astonish progress climate change years deadlock say andrew steer head world resources institute think-tank global pacts contrast nationalist force help trump win u.s. republican nomination president side atlantic britain vote june leave european union paris agreement enter force pass threshold last month ratification 55 nations represent 55 percent greenhouse gas emissions tally 87 nations represent 60 percent emissions unite state alone account 18 percent global emissions vienna convention law treaties trump could renounce u.s. share argue entire entry force invalid entry force go one way reverse say elliot diringer executive vice-president non-partisan center climate energy solutions washington could legal challenge u.s. republican party platform say obama democrat use executive power ratify agreement submit senate would almost certainly reject governments marrakesh try bolster pact set many goals cut greenhouse gas emissions 2025 2030. governments pressure spell rather leave successors core paris agreement promise limit global warm well degrees celsius 3.6 fahrenheit pre-industrial time current pledge limit emissions weak allow temperatures rise perhaps 3c 5.4f 2100. diplomats expect take two years write rule book accord among difficulties agreement let countries set target emissions free-for-all design help ensure wide support odds need central set rule monitor report greenhouse gas emissions factories cars farm power plant irrespective rule price renewable energies fall sharply prompt shift fossil fuel u.s. climate envoy jonathan pershing say wind solar energy account two-thirds new electricity generate capacity instal unite state 2015 u.s. solar industry employ people coal say still trump say promote u.s. coal oil industries safeguard domestic job national security say shift fossil fuel would force unite state beg oil middle east suppliers backers paris climate pact play trump threat deal election loom