Associated Press: Thousands of people calling for a deal on climate change at next week’s United Nations conference in Copenhagen marched through central London on Saturday, encircling the Houses of Parliament in a human wave of blue-clad demonstrators. London’s Metropolitan Police said about 20,000 people joined the Stop Climate Chaos march, which began at Grosvenor Square and wound its way to the Parliament building on the River Thames. Organizers put the turnout at 40,000. "We wanted to make …