EDINBURGH, Scotland – Some pelted police with earth torn from flower beds. Others kissed officers’ riot shields, leaving lipstick marks. A man serenaded protesters with a bagpipe.

Anger, humor, and the bizarre coursed through yesterday’s demonstrations by hundreds of black-clad anarchists and other protesters in Scotland’s capital, as they sought to keep the pressure on world leaders ahead of the summit of G-8 industrialized nations.

Police carrying shields or on horseback locked down entire streets in Edinburgh. Authorities advised businesses to close, describing the protesters’ behavior as threatening.

Groups of up to 200 demonstrators – some dressed as clowns – roamed Edinburgh, banging drums, blowing whistles, and taunting officers. A protester dressed in a rabbit outfit waved a carrot at police horses. Police said they had arrested nearly 30 protesters.

The protests were aimed at tomorrow’s meeting of the Group of Eight industrialized nations at the nearby Gleneagles Hotel, where world leaders will discuss African poverty and ways to deal with global warming.

Some demonstrators are demanding that leaders take urgent action on world poverty and the environment, while anarchists don’t want the summit itself to go ahead.

The protests followed the Live 8 series of concerts around the world, in which rock stars and celebrities urged the G-8 leaders to take decisive steps to end African poverty.

Prime Minister Blair struggled to unite world powers on fighting global warming ahead of the summit, raising the question of whether he would consider leaving a skeptical America behind to secure an agreement among the other leaders.

Mr. Blair has made climate change a central issue of Britain’s G-8 presidency, describing it as “probably the most serious threat we face.” He wants an agreement among G-8 leaders on the scientific threat posed by global warming and the urgent need for action.

“Our expectations on a unanimous … strong agreement are very low, because George Bush isn’t going to change his mind,” said Stephanie Tunmore of the environmental group Greenpeace. “We would hope that wouldn’t stop the other G-8 leaders coming out with a strong statement.”

“What we would really like to see is a very, very strong statement on the science” underlying global warming, Ms. Tunmore said. Underlining trans-Atlantic differences, President Chirac said Sunday that climate change is a matter of increasing concern.

“That’s why we have indicated clearly to our partners that we could only accept a solution if it took account of a certain number of realities,” he said.

Mr. Chirac called for a statement on the issue to include specific mention of the Kyoto Protocol, which took effect in February and obliges participating industrialized nations to reduce their combined greenhouse gas emissions by 5.2 percent below their 1990 levels by 2012.

President Bush, in an interview with Britain’s ITV television yesterday, renewed his insistence that Washington would not sign the Kyoto Protocol or any similar deals limiting gas emissions. Still, he described climate change as “a significant, long-term issue that we’ve got to deal with” and acknowledged that human activity is “to some extent” to blame.

“My hope is – and I think the hope of Tony Blair is – to move beyond the Kyoto debate and to collaborate on new technologies that will enable the United States and other countries to diversify away from fossil fuels so that the air will be cleaner and that we have the economic and national security that comes from less dependence on foreign sources of oil,” Mr. Bush said.

The director of the World Wide Fund for Nature, Jennifer Morgan, charged that “the Bush administration is not only failing to deal with the threat of climate change but is also actively trying to water down the G8’s efforts on the issues.”

“If the U.S. is lagging behind, then it’s time for them to be left behind,” she said.

A British official involved in presummit talks said yesterday that G-8 leaders could reach an accord on global warming that recognizes the problem and the need to combat it.

The discussions “were pretty intense” on the complex issues of climate change and the effect farm subsidies have on global trade, especially in Africa, said Sir Michael Jay, Mr. Blair’s representative.

“But I do sense a real desire, if possible, to reach an agreement on these two issues,” he said at a news conference.

At the protest, about 10 officers were surrounded by demonstrators as they tried to make an arrest, and were pelted with clods of earth torn from flower beds in a park.

Organizer called the protest the “carnival for full enjoyment” and it brought several streets to a standstill.

Demonstrators ripped up sections of sidewalk and lobbed bricks at a line of officers clad in body armor and helmets. Police repeatedly charged the crowd using their shields to push protesters back, but came under a barrage of bottles and empty beer cans.