REUTERS - The world's biggest emitters of global-warming greenhouse gases met behind closed doors on Wednesday for a U.S.-sponsored conference as protesters pointed out Hawaii's vulnerability to climate change.

To understand the climate-change debate, it helps to understand the jargon, a mixture of diplomatese, pundit-speak and techno-talk. Here are some terms used at meetings on global warming.

KYOTO - Short for Kyoto Protocol, an international agreement adopted in 1997 in Kyoto, Japan, which sets binding targets for emission of greenhouse gases that spur global warming. Under this agreement, developed countries are to cut their emissions by an average of 5.2 percent below what they were in 1990. The United States rejected this agreement, arguing that it unfairly exempts developing countries like China and India. The Kyoto Protocol expires in 2012.

FRAMEWORK - The U.N. Framework Convention on Climate Change, a 1992 agreement that the United States and 191 other countries have signed. Like Kyoto, it seeks to keep greenhouse gases from hitting a level that would interfere with climate, but has no legally binding requirements.

GREENHOUSE GASES - Chemicals that trap the sun's heat near the Earth like a blanket. These substances include carbon dioxide, which is emitted by humans and all other creatures that breathe air. They are also emitted by coal-fired power plants and petroleum-fueled vehicles. They are not the most intense greenhouse gas -- methane is 10 times more powerful in contributing to global warming -- but carbon dioxide from fossil fuel consumption produces 82 percent of the world's human-generated greenhouse gases.

CAP AND TRADE - Policy tool that sets limits on harmful emissions, giving allowances to affected industries and countries within these limits, or caps. Those with emissions above the cap can trade with those with emissions below it. Also known as emissions trading.

CARBON FOOTPRINT - A measure of the impact of human activities on the environment in terms of the amount of greenhouse gases they produce, measured in units of carbon dioxide.

CARBON OFFSETS - Paying to make up for carbon emissions. One example is planting trees or contributing to a wind farm to make up for the carbon dioxide emitted during air or car travel.

U.N. CLIMATE PANEL - Intergovernmental Panel on Climate Change, established in 1988 by the World Meteorological Organization and the U.N. Environment Program, which has produced a series of reports on climate change. Their fourth assessment, issued in 2007, said it is 90 percent probable global warming is occurring and humans contribute to it.

BALI - Indonesian island where scientists and policy makers gathered in December to discuss how to cut climate-warming emissions after the Kyoto Protocol expires in 2012. Nearly 200 nations agreed at U.N.-led talks there to launch negotiations on a new pact to fight global warming after a reversal by the United States allowed a breakthrough. Despite its turnaround in the meeting, which approved a "roadmap" for two years of negotiations to adopt a new treaty to succeed Kyoto beyond 2012, the White House said it still had "serious concerns" about the way forward.

MAJOR ECONOMIES - The world's biggest emitters of carbon dioxide. They are: the United States, China, the 27-member European Union, Russia, India, Japan, Brazil, Canada, Mexico, Indonesia, South Korea, Australia and South Africa.