Russian President Vladimir Putin has signed a bill confirming Russia's ratification of the Kyoto Protocol, the international agreement aimed at curbing global warming. Russia's ratification makes the protocol internationally binding. The Kremlin said Mr. Putin signed the bill late Thursday. The pact will become effective three months after Mr. Putin notifies the United Nations of the ratification. The treaty was adopted at a UN conference on climate change in 1997, but the United States rejected it in March of 2001. Countries that have ratified the protocol will commit to reduce their emissions of carbon dioxide and other greenhouse gasses that are thought to contribute to global warming. Critics of the agreement say it will retard the economic growth of industrial nations. Some information for this report provided by AP, AFP and Reuters.