As the United States looks to reform its health care system and expand access to the uninsured, countries that have moved toward universal health care may offer lessons.

Interest in nuclear power is increasing, but securing adequate uranium supplies for nuclear fuel faces challenges ranging from a flagging mining sector to fears of nuclear weapons proliferation.

Loss of forests is a major contributor to greenhouse-gas emissions. Plans to devise a policy tool for using trees for carbon dioxide sequestration are now under way.

President Barack Obama says he will seek vigorous climate-change policy. Efforts to curb greenhouse gases pose considerable economic pitfalls, as well as opportunities.

China has grown into a trading giant, but recent concerns over the safety of Chinese food and drugs have increased worries that China’s production may have outpaced the country’s policing capacity.