RIYADH, Nov 16 (Reuters) OPEC leaders meeting in Saudi Arabia are expected to back the fight against global warming at a two-day summit that could offer the populist leaders of Iran and Venezuela the chance to grandstand against Washington.
Security will be so tight in the Saudi capital -- which has been hit by militant attacks since 2003 -- that a two-day public holiday has been declared as many central roads are closed.
Leaders arriving for the summit, which opens at 7 p.m.
Riyadh time (1600 GMT), include Iran's President Mahmoud Ahmadinejad and Venezuelan President Hugo Chavez.
Both are engaged in diplomatic disputes with the United States, to which Saudi Arabia is closely allied, that have helped drive world oil prices to nearly 0 per barrel.
Ahmedinejad's visit could offer Saudi leaders -- who diplomats say do not like the firebrand Iranian -- another chance to engage in diplomacy over a nuclear programme that has raised the possibility of a regional arms race.
The United States, backed by Saudi Arabia and Western powers, suspects Iran wants to use its nuclear energy programme as a cover to build atomic bombs, which Iran denies.
Fears of a war in the region if the United States or its ally Israel stage an attack on Iran helped push oil to a record .62 per barrel last week.
Western consumer nations feeling the pinch from high prices have put pressure on OPEC to increase production, but ministers say there is little the group can do as factors beyond its control are driving the market. Venezuela's oil minister said on Friday there was no need to pump more oil.
Any decision on whether to raise OPEC output will be left to a meeting in Abu Dhabi next month, OPEC ministers said this week. Instead, the summit's final communique will focus on tackling climate change, the long-term reliability of oil supplies and energy's role in the developing world.
''It will emphasise the role of OPEC countries and oil producers in mitigating global warming,'' said one delegate. But it was not clear if OPEC, which pumps more than a third of the world's oil, would commit to funding research.
OPEC Secretary General, Abdullah al-Badri, said OPEC would be willing to play its part in developing carbon capture and storage (CCS) technology. The summit ends on Sunday.
DOLLAR EFFECT A closed session on Friday of foreign and finance ministers voted against a proposal by Iran and Venezuela to highlight concern over dollar weakness in the summit communique.
''My fear is that any mention that OPEC makes of studying the issue of the dollar, will in itself have an impact,'' Saudi foreign minister Saud al-Faisal told the session, part of which was mistakenly broadcast live to reporters.
The dollar's fall in value against other major currencies helped fuel oil's rally, but has also reduced the purchasing power of the Organization of the Petroleum Exporting Countries.
Earlier this week, Chavez proposed OPEC finance social development programmes for poor countries and increase its diplomatic activity, seeking to put his self-styled socialist revolution on the global stage.
A member of the Venezuelan delegation said OPEC officials would try to keep Chavez away from the media.
With the summit, normally media-shy Saudi Arabia boosts its image as a robust international player after hosting an Arab summit earlier this year and leading diplomatic efforts to ease tension in Lebanon and the Palestinian territories.
This month, in a bid to defuse the standoff with Washington, Saudi Arabia proposed the setting-up of a consortium to provide Iran with enriched uranium for peaceful purposes. Iran said it would not halt its own enrichment programme.
Gulf Arab countries, including OPEC producers Saudi Arabia, Kuwait, Qatar and the United Arab Emirates, have said they will start a nuclear energy programme of their own.
REUTERS BJR DS1545