STOCKHOLM (AP) — Scientists can now say with extreme confidence that human activity is the dominant cause of the global warming observed since the 1950s, a new report by an international scientific group said Friday.

Calling man-made warming "extremely likely," the Intergovernmental Panel on Climate Change used the strongest words yet on the issue as it adopted its assessment on the state of the climate system.

In its previous assessment, in 2007, the U.N.-sponsored panel said it was "very likely" that global warming was man-made.

One of the most controversial subjects in the report was how to deal with a purported slowdown in warming in the past 15 years. Climate skeptics say this "hiatus" casts doubt on the scientific consensus on climate change.

Many governments had objections over how the issue was treated in earlier drafts and some had called for it to be deleted altogether.

In the end, the IPCC made only a brief mention of the issue in the summary for policymakers, stressing that short-term records are sensitive to natural variability and don't in general reflect long-term trends.

"An old rule says that climate-relevant trends should not be calculated for periods less than around 30 years," said Thomas Stocker, co-chair of the group that wrote the report.

Many scientists say the purported slowdown reflects random climate fluctuations and an unusually hot year, 1998, picked as a starting point for charting temperatures. Another leading hypothesis is that heat is settling temporarily in the oceans, but that wasn't included in the summary.

Stocker said there wasn't enough literature on "this emerging question."

The IPCC said the evidence of climate change has grown thanks to more and better observations, a clearer understanding of the climate system and improved models to analyze the impact of rising temperatures.

"Our assessment of the science finds that the atmosphere and ocean have warmed, the amount of snow and ice has diminished, the global mean sea level has risen and the concentrations of greenhouse gases have increased," said Qin Dahe, co-chair of the working group that wrote the report.

The full 2,000-page report isn't going to be released until Monday, but the summary for policymakers with the key findings was published Friday. It contained few surprises as many of the findings had been leaked in advance.

As expected, the IPCC raised its projections of the rise in sea levels to 10-32 inches (26-82 centimeters) by the end of the century. The previous report predicted a rise of 7-23 inches (18-59 centimeters).

But it also changed its estimate of how sensitive the climate is to an increase in CO2 concentrations, lowering the lower end of a range given in the previous report. In 2007, the IPCC said that a doubling of CO2 concentrations would likely result in 2-4.5 C (3.6-8.1 F) degrees of warming. This time it restored the lower end of that range to what it was in previous reports, 1.5 C (2.7 F).

The IPCC assessments are important because they form the scientific basis of U.N. negotiations on a new climate deal. Governments are supposed to finish that agreement in 2015, but it's unclear whether they will commit to the emissions cuts that scientists say will be necessary to keep the temperature below a limit at which the worst effects of climate change can be avoided.

Using four scenarios with different emissions controls, the report projected that global average temperatures would rise by 0.3 to 4.8 degrees C by the end of the century. That's 0.5-8.6 F.

Only the lowest scenario, which was based on major cuts in CO2 emissions and is considered unlikely, came in below the 2-degree C (3.6 F) limit that countries have set as their target in the climate talks to avoid the worst impacts of warming.

"This is yet another wakeup call: Those who deny the science or choose excuses over action are playing with fire," U.S. Secretary of State John Kerry said in a statement. "Once again, the science grows clearer, the case grows more compelling, and the costs of inaction grow beyond anything that anyone with conscience or common sense should be willing to even contemplate."

At this point, emissions keep rising mainly due to rapid growth in China and other emerging economies. They say rich countries should take the lead on emissions cuts because they've pumped carbon into the atmosphere for longer.

Climate activists said the report should spur governments to action.

"There are few surprises in this report but the increase in the confidence around many observations just validates what we are seeing happening around us," said Samantha Smith, of the World Wildlife Fund.

The report adopted Friday deals with the physical science of climate change. Next year, the IPCC will adopt reports on the impacts of global warming, strategies to fight it and a synthesis of all three reports.

WASHINGTON (AP) — A potential government shutdown hurtling ever closer, the Democratic-led Senate moved Friday toward approving legislation keeping federal agencies from locking their doors on Tuesday. But disputes with the Republican-run House and among GOP lawmakers themselves ensure the battle will spill into the weekend at least, and quite possibly beyond.

The result: a high-stakes showdown that is playing out in a climate of chaos, infighting and unpredictability that is extraordinary even by congressional standards. Reflecting the building drama, Senate Chaplain Barry Black opened Friday's session with a prayer that included, "Lord, deliver us from governing by crisis."

The Senate planned votes later Friday on the measure preventing a shutdown. Senators were expected to pass it after derailing a conservative effort to block the bill and after removing House-approved language that strips money from President Barack Obama's health care law.

That would bounce the legislation back to the House, where GOP leaders already have declared the pared-down Senate to be insufficient.

With conservatives insisting that the shutdown bill and a separate debt limit measure present an opportunity to demolish the Affordable Care Act and slash spending, House leaders were not saying what, if any, decisions they had made on strategy.

No votes on the budget bill were expected in the House until the weekend at least. The Senate measure would allow hundreds of thousands of employees at dozens of agencies to continue working, while shielding lawmakers from public scorn.

GOP disunity over what to include in the debt limit measure forced leaders to indefinitely delay that legislation, which is aimed at preventing a damaging, first-ever federal default that the Obama administration has warned could otherwise occur by Oct. 17.

At one point Thursday, GOP divisions burst into full view on the Senate floor as a pair of conservatives, Sens. Ted Cruz of Texas and Mike Lee of Utah, forced the Senate to wait until Friday to approve its bill preventing a shutdown.

"The American people are watching this" but expected the vote Friday or Saturday, said Lee, who asked Senate Majority Leader Harry Reid, D-Nev., to not hold the roll call on Thursday.

Reid accused the conservatives of "a big, big stall."

He said he wanted to return the Senate bill to the House as quickly as possible to give GOP leaders there more time to send back an amended bill and avoid a shutdown.

Lee's request also prompted Sen. Bob Corker, R-Tenn., to engage in an icy exchange with Cruz in which Corker accused the two conservatives of seeking a delay because they had emailed their supporters to watch debate on the legislation on Friday and had "turned this into a show."

"And that is taking priority over getting legislation back to the House so they can take action before the country's government shuts down," said Corker, barely masking his disdain.

Just a day earlier, Cruz, a possible 2016 presidential contender, ended a 21-hour speech urging lawmakers to block the Senate bill before Reid amends it to drop the language defunding Obama's 2010 health care law.

That talkathon, and Cruz's strategy, has garnered widespread praise from supporters around the country and become a focus of fundraising appeals by conservative groups.

"We are not going to be complicit in giving Harry Reid the ability to fund Obamacare," Cruz said Thursday.

But Cruz and Lee's effort has earned derision from many GOP colleagues, who see it as a ploy that is doomed and increases the odds of legislative delays that threaten a shutdown. Most Republicans want to avoid a shutdown, fearing blame from voters.

Asked Thursday whether he envisions the House approving a simple Senate-passed bill keeping the government open, House Speaker John Boehner, R-Ohio, told reporters, "I don't see that happening." GOP lawmakers said he signaled the same thing at a closed-door meeting Thursday.

They said the House might insert provisions into the shutdown bill repealing an unpopular tax on medical devices that helps pay for Obama's health care overhaul, or erasing federal subsidies for Congress' own health care coverage. They could then dare the Senate to reject the overall measure — and face the fallout from the government shutdown that would result.

But lawmakers and GOP aides cautioned that no decisions had been made, in part because it was unclear whether even those provisions would help win enough votes for House passage.

The debt limit bill was even more complicated and potentially dangerous. Many analysts think even the serious threat of a federal default would jar the economy — for which neither party would relish being blamed.

In an attempt to build support, House GOP leaders considered adding a stack of provisions.

A one-year delay of "Obamacare," expedited congressional work on tax reform and clearing hurdles to the proposed Keystone XL oil pipeline from Canada to Texas were considered certainties. Other possibilities included boosts in Medicare costs for higher earners, land transfers in California and Oregon, and repealing Federal Communications Commission restraints on Internet providers' ability to control available content.

Even so, many conservatives said the debt limit bill lacked sufficient spending cuts.

"It definitely has a lot of goodies in it, things that arguably would grow the economy and arguably would generate more revenue," said Rep. Mo Brooks, R-Ala. "But still you have to address the spending problem."