This week, climate policy headlines from around the world include a new study that ranks soot as the second-worst cause of climate change, an estimated $700 billion cost to avoid further temperature rise, and Germany’s solar development.

Elinor Benami, Chiara Trabacchi, Hermann Amecke, and Karen Laughlin contributed headlines to this edition of Policy Watch.

Study: Black carbon ranks as second-biggest human cause of global warming
Soot ranks as the second-largest human contributor to climate change, exerting twice as much of an impact as previously thought, according to an analysis released Tuesday.

The four-year, 232-page study of black carbon, published in the Journal of Geophysical Research: Atmospheres, shows that short-lived pollution known as soot, such as emissions from diesel engines and wood-fired stoves, has about two-thirds the climate impact of carbon dioxide. The analysis has pushed methane, which comes from landfills and other forces, into third place as a human contributor to global warming.  Full article.

Beijing tries to clean up its act
China’s smog-ridden capital issued an unprecedented set of new anti-pollution measures this past weekend, as the authorities scramble to respond to rising public pressure over the city’s deteriorating air quality.

The far-reaching measures target everything from outdoor barbecues and dusty construction sites, to paint fumes and idling car engines, representing the city’s broadest effort yet to fight the persistent pollution haze over Beijing. Full article.

California carbon trading takes off
California’s official carbon market kicked off January 1 with an uptick in trading, as businesses began accounting for their greenhouse gas emissions in earnest.

No lawsuit against the program accompanied the official start date, as many had anticipated. Instead, appetite for California’s carbon allowances grew, reflecting confidence in the burgeoning, first-in-the-nation economywide greenhouse gas market, traders said. Full article.

German solar boom continues despite support cuts
Germany’s subsidy-backed solar power installations from January through to November 2012 indicate that full-year figures are set to come close to last year’s record, highlighting spiraling costs for consumers.

Figures issued by the country’s energy regulator, the Bundesnetzagentur, at the turn of the year showed January to November 2012 installations rose to nearly 7,300 MW and that November installations alone totaled 435.3 MW compared with 659.3 MW in November 2011. Full article.

Study: Averting climate change may cost $700 billion a year
About $700 billion a year of new spending on renewable power, low-carbon transport and energy efficiency is needed to meet the United Nations goal to cap temperature rises, a report for the World Economic Forum showed. Full article.