Greenhouse Effect

California companies are rushing to voluntarily register their greenhouse gases before the launch of a major statewide program this year to address global warming. A total of 116 companies registered their emissions with the California Climate Action Registry in December -- more than doubling the number of companies enrolled to 221.

More pregnant polar bears in Alaska are digging snow dens on land instead of sea ice -- a phenomenon that researchers say is probably related to global warming. From 1985 to 1994, 62% of the bears studied dug dens on sea ice. From 1998 to 2004, just 37% gave birth on sea ice, according to the study by three U.S. Geological Survey researchers. Bears that continued to den on ice moved east in the Beaufort Sea off Alaska's northern coast, away from ice that was thinner or unstable.

All of a sudden, global warming is hot. After years of languishing on Capitol Hill, efforts to curb global warming have picked up momentum, powered by a growing bipartisan belief that climate change can no longer be ignored. Speaker Nancy Pelosi (D-San Francisco) has declared it a top priority for the House. Presidential candidates from both parties call it one of the biggest issues faced by the next occupant of the White House. Even President Bush, long a skeptic, is sounding the alarm.

Following through on the Democratic Party's pledge to conduct aggressive oversight, Rep. Henry A. Waxman (D-Los Angeles) headed toward a possible confrontation Tuesday with the White House over his demands for documents that could show whether the Bush administration interfered with the work of government climate scientists to downplay the dangers of global warming.

In his first major action as California attorney general, Jerry Brown signaled to the nation's Big Six automakers Thursday that he would like to reach a compromise in a high-stakes legal battle over how to curb global warming. But Brown left no doubt that he would press a lawsuit by the state against the companies if they failed to reduce greenhouse gas emissions from car tailpipes.

In the strongest language it has ever used, a United Nations panel says global warming is "very likely" caused by human activities and has become a runaway train that cannot be stopped. The warming of Earth and increases in sea levels "would continue for centuries ... even if greenhouse gas concentrations were to be stabilized," according to a 20-page summary of the report that was leaked to wire services. The summary of the fourth report by the U.N.'

A United Nations report released Friday that blames humans for the "runaway train" of global warming has abruptly shifted the international debate from "Are humans to blame?" to "What are we going to do about it?" "The world's scientists have spoken," said Timothy E. Wirth, president of the United Nations Foundation. "It is time now to hear from the world's policymakers. The so-called and long-overstated 'debate' about global warming is now over."

Everybody in the United States could switch from cars to bicycles. The Chinese could close all their factories. Europe could give up electricity and return to the age of the lantern. But all those steps together would not come close to stopping global warming.

When Doug Gronau looks out the window of his Iowa farmhouse, he sees a profitable investment in the effort to stop global warming. Most people see cornfields. His cropland, which he is prohibited from tilling, is a greenhouse gas credit, packaged and sold on the Chicago Climate Exchange. An anonymous trader snapped up the field's ability to absorb carbon dioxide to offset -- on paper -- a tiny portion of the carbon dioxide emitted by some distant factory. Gronau, 57, expects a check for $2,800.

Airline tycoon Richard Branson announced Friday that he would award a $25-million prize to the first person to come up with a way of scrubbing greenhouse gases from the atmosphere and alleviate global warming. The prize will initially be open for five years, with ideas assessed by a panel of judges. The winning technique must remove 1 billion tons of carbon gases a year from the atmosphere for 10 years -- with $5 million going to the inventor at the start and $20 million at the end.