Climate change is the greatest environmental threat humanity has ever faced and the biggest challenge. Climate change is caused by the build-up of greenhouse gases, which are released from burning fossil fuels and the destruction of ancient forests and peatlands.
Today our planet is hotter than it has been in 2,000 years. Global warming cannot be explained by the natural mechanisms that caused previous warm periods. The overwhelming majority of climate scientists all agree: the rising global temperatures we've recently experienced are due to human activity.
Climate change is caused by the buildup of greenhouse gases in our atmosphere. These gases trap heat within the atmosphere, raising the average temperature of the planet. This in turn affects our oceans and climate, with devastating impacts on people and environments.
The largest source of greenhouse gases is the burning of fossil fuels, which include coal, oil, and natural gas. Burning fossil fuels releases carbon dioxide, the most important greenhouse gas emitted by human activities.
Deforestation is another major cause of climate change. Ancient forests and peatlands have stored up enormous quantities of carbon over the centuries, and their destruction releases that carbon into the atmosphere. That's why ending deforestation in our ancient forests in Indonesia, the Congo, and the Amazon is crucial to stopping climate change.
Other sources of greenhouse gases include agriculture and especially raising livestock, which releases methane, as well as refrigeration, which releases fluorinated gases. Both methane and fluorinated gases are powerful contributors to global warming.
China, coal, and climate change
The state-owned, coal-burning Xuanwei Power Station in Yunnan province
Though it's a latecomer to industrialization, China's rapid economic development has made it the world's number one emitter of greenhouse gases. The booming economy has lifted millions out of poverty, but at huge environmental cost.
China's astronomic growth and skyrocketing greenhouse gas emissions both have the same cause: black, sooty coal. More than 70% of China's energy is supplied by coal, which in turn contributes 80% of the country's carbon dioxide emissions. Coal provides electricity to power factories, cities, businesses and homes. It poisons our atmosphere, our rivers and mountains and our lungs.
Unless China end its reliance on coal, it will be nearly impossible for the world to avoid runaway climate change.
That's why Greenpeace is working against coal in China.
Consequences of climate change: Severe drought in Yunnan in March, 2010
The impacts of climate change are already being felt. Average global temperatures have risen every decade since the 1970s. 2010 tied 2005 as the hottest year on record. Overall, the 10 hottest years on record have all occurred in the last 13 years.
Extreme weather events – droughts, floods and major typhoons – are becoming more common and destroying farmlands. China's already stressed water resources are drying out even further. Glaciers, permafrost and sea ice are disappearing, while sea levels are rising and coral reefs dying. The impacts of climate change are already responsible for killing an estimated 315,000 people every year, and damaging ecosystems.
How much climate change can we bear?
An average temperature rise of around 1.3°C above pre-industrial levels is already inevitable and will bring with it terrible impacts worldwide.
Limiting warming to under 2°C (3.6°F) is considered vital to preventing the worst effects of climate change. Some studies say we have 10 years or less to tackle emissions if we are to stay below that threshold.
If our greenhouse gas emissions are not brought under control, the speed of climate change over the next hundred years will be faster than anything known since before the dawn of civilisation.
There is a very real possibility that temperature rises above a tipping point will result in runaway climate change: global warming could spiral out of control, resulting in a sudden and irreversible shift. No one knows how much warming it would take to trigger such a devastating scenario.