By Valerie Volcovici

NEW YORK (Reuters) - With crises from Islamic State to Ebola competing for attention, the United Nations on Tuesday will zero in on climate change, giving leaders from 125 countries a platform to explain how they plan to address the issue.

A huge march to call for international action on climate change, which brought as many as 400,000 people to the streets of New York on Sunday, set the tone for the summit spearheaded by U.N. Secretary-General Ban Ki-moon.

The private sector also helped create a buzz around the summit, with corporate chief executives like Apple's Tim Cook and Ikea's [IKEA.UL] Peter Agnefjäll declaring a variety of voluntary measures to reduce their carbon emissions.

Among the most highly anticipated speakers on Tuesday will be U.S. President Barack Obama, whose administration has sought to make U.S. leadership on climate change a legacy goal.

The White House announced on Tuesday that Obama would issue an executive order to require federal agencies to ensure their international development programs and investments are designed to help communities adapt to the impacts of climate change.

Secretary of State John Kerry hinted on Monday at what else Obama is expected to highlight when he takes the podium.

“Over the past five years, the United States has actually done more to reduce the threat of climate change domestically and with the help of our international partners than in all of the 20 years before that,” he said.

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Demonstrators in animal costumes walk in the "People's Climate March" in central Londo …

He added the United States was on track to meet its international pledge to cut its greenhouse gas emissions 17 percent below 2005 levels by 2020 because of Obama's climate policies.

Leaders who will be absent from Tuesday's gathering include Chinese President Xi Jinping and Indian Prime Minister Narendra Modi, who represent the first and fourth biggest greenhouse gas polluters.

SEEKING POLITICAL MOMENTUM

The summit is meant to add political momentum to a U.N. process to negotiate a climate-change agreement in Paris by 2015.

By holding the high-level gathering almost 16 months before the Paris deadline, Ban has ensured that climate change will be at the forefront of every leader’s agenda, EU climate change commissioner Connie Hedegaard told Reuters in an interview.

“With all the outreach we need to do in this area, it is crucial that all the foreign ministries are taking this up,” she said.

She said the fact that foreign ministers, including Kerry and France's Laurent Fabius, discussed climate deal negotiations on Sunday in a meeting of the world's 17 biggest emitting countries was a sign that the issue had become a policy priority.

But Hedegaard and Fabius highlighted what could be a roadblock to a Paris pact – agreement on the legal basis of the final deal.

U.S. negotiators have acknowledged that a deeply polarized Congress is unlikely to ratify a legally binding U.N. treaty.

“We have to have a legal agreement, otherwise it will be just words,” Fabius said on Monday.

Ban said there was a greater sense of "anxiety" around the issue than at previous gatherings in New York in 2007 and Copenhagen in 2009.

On Monday, he summed up the risk of countries failing to cement a climate deal.

"If we cannot all swim together, we will sink," he said.

(Reporting by Valerie Volcovici; Editing by Peter Cooney)

How the world plans to address climate change

Leaders from 125 countries — including U.S. President Barack Obama — are expected as a U.N. summit begins.
Deadline

Washington (AFP) - A US-led air attack against jihadists in Syria targeted Al-Qaeda's Khorasan group because it was on the verge of carrying out "major attacks" against the West, the US military said Tuesday.

The Americans pounded Khorasan targets in Syria with Tomahawk cruise missiles to counter the mounting threat posed by the group, said Lieutenant General William Mayville, director of operations for the US Joint Chiefs of Staff.

"Intelligence reports indicated that the group was in the final stages of plans to execute major attacks against western targets and potentially the US homeland," Mayville told reporters.

The strikes against the Khorasan militants early Tuesday were separate from a wave of bombing raids led by the United States and joined by several Arab countries that targeted the Islamic State group.

Earlier, the Pentagon had said that US air strikes killed Khorasan members hatching plots against Western targets.

US Central Command, which oversees American forces in the Middle East, had announced that American forces carried out eight air strikes against Khorasan group targets west of Aleppo.

Mayville said more than 40 Tomahawk missiles were launched from naval ships in the Gulf and the Red Sea, and that "the majority of the Tomahawk strikes were against Khorasan."

The Khorasan group was not focused on battling the Syrian regime or aiding the Syrian people but instead is "establishing roots in Syria in order to advance attacks against the West and the homeland," he said.

Speaking of the broader air campaign that included Arab states, Pentagon spokesman Rear Admiral John Kirby said "our initial indication is that these strikes were very successful."

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President Barack Obama speaks about the participation of five Arab nations in airstrikes against mil …

And he signaled that more bombing raids in Syria were to come.

"I can tell you that last night's strikes were only the beginning," Kirby said.

President Barack Obama ordered the bombing raids in Syria last Thursday, a day after conferring with commanders at Central Command headquarters in Tampa, Florida, the White House said.

- Three waves of air strikes -

The US military was "unaware of any civilian casualties" from the strikes and the air attack was planned to minimize the risk to civilians in the area, Mayville said.

The general acknowledged there was evidence IS fighters were already dispersing and moving towards population centers to hide from the sights of US attack aircraft.

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In this picture downloaded from the US Navy website and taken on September 23, 2013, an F/A-18C Horn …

But he said there was no need at the moment to bring in tactical air controllers on the ground to direct bombing raids to avoid civilian casualties.

The first wave of strikes Tuesday featured mainly Tomahawk cruise missiles, the second wave had US fighter planes and B-1 bombers hitting targets and then the third wave included Arab warplanes and American F/A-18 jets flying from an aircraft carrier, the George H.W. Bush, in the Gulf, Mayville said.

IS group leaders were not specifically targeted in the raids but US and Arab aircraft aimed at "command and control" centers, he said.

The operation broke new ground with four Arab countries sending in aircraft to take part, which US officials said demonstrated regional states were committed to fighting the IS extremists.

Bahrain, Jordan, Saudi Arabia and the United Arab Emirates played direct roles in the operation while Qatar played a supporting role, officials said, without providing details.

The "preponderance" of bombs dropped were from US aircraft, Mayville said.

The Damascus regime views the IS group as an adversary, and the White House said President Bashar al-Assad's government was told in advance about the plan to attack -- but in general terms.

The US ambassador to the United Nations, Samantha Power, passed the word to her Syrian counterpart, said Ben Rhodes, deputy national security adviser.

But he and other officials insisted the air strikes were not coordinated in any way with Assad's army.

Asked if Syrian regime air defense radar locked onto to US or allied aircraft, Mayville suggested the regime did not target the incoming warplanes.

The general said "radar acquisition on the part of Syria, I would characterize as passive."

The overnight operation was the first in which the US military's costly, new F-22 Raptor fighter jet was used in combat.

The general showed reporters aerial photos of targets bombed by the stealthy F-22s, with the planes unleashing precision-guided bombs on an IS command and control site in a building.

"This strike was the first time the F-22 was used in a combat role," Mayville said. He said the F-22s "destroyed" the intended target.

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By Kay Johnson and Hamid Shalizi

KABUL (Reuters) - Outgoing President Hamid Karzai on Tuesday blamed the United States for Afghanistan's long war in a final swipe at the country that helped bring him to power 13 years ago but towards which he has become increasingly bitter.

His farewell speech came days ahead of the swearing in of a new president, Ashraf Ghani, after months of turmoil over a disputed election that ended in a power-sharing deal, yet to be tested, with rival Abdullah Abdullah who will fill the role of chief executive.

Karzai blamed both the United States and neighboring Pakistan for the continuing war with the Taliban-led insurgency and warned the new government to be "extra cautious in relations with the U.S. and the West".

The conflict kills thousands of Afghans each year and has claimed the lives of more than 2,200 American and other international forces in Afghanistan.

"One of the reasons was that the Americans did not want peace because they had their own agenda and objectives," Karzai said. He did not elaborate, but in the past has suggested continued violence has been an excuse for the United States to keep bases in the country.

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Afghan President Hamid Karzai speaks during his farewell ceremony at the presidential palace in Kabu …

U.S. Ambassador to Afghanistan James Cunningham called Karzai's comments "ungracious and ungrateful".

"It makes me kind of sad. His remarks, which were uncalled for, do a disservice to the American people and dishonor the sacrifices made by Americans here," Cunningham said.

Karzai also accused Pakistani power players of trying to control his country's foreign policy.

"Today, I tell you again that the war in Afghanistan is not our war, but imposed on us and we are the victims," Karzai said. "No peace will arrive unless the U.S. or Pakistan want it."

In recent years, Karzai has denounced the United States for the deaths of Afghan civilians in air strikes and for holding suspected Afghan militants prisoner without trial. The relationship deteriorated to near breaking point this year when Karzai refused to sign a security pact with the United States.

He said he had traveled to Pakistan, where much of the Taliban's leadership is believed to be based, at least 20 times seeking a negotiated end to the war, but his efforts were thwarted.

Pakistan's embassy in Kabul had no immediate comment on Karzai's speech.

Karzai has been in power since 2001 after being plucked from virtual obscurity by the United States after the overthrow of the Taliban's radical Islamist government for sheltering al Qaeda's leadership after the 9/11 attacks on the United States.

The deterioration of his relationship with the West was seen by some as an effort to shape his legacy as an independent leader rather than a U.S. puppet as maintained by the Taliban.

Karzai was barred by the constitution from running for a third term this year.

(Editing by Nick Macfie and Janet Lawrence)

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