Short answers, pulled from the story.
Carbon dioxide from burning fossil fuels is the main cause of climate change. Burning oil, coal, and gas emitted an estimated 37.4 billion tonnes of CO2-equivalent in 2023, with coal-fired power stations as the single largest individual source at over 20% of global greenhouse gas emissions.
China is the world's largest greenhouse gas emitter, releasing around 10 billion tonnes each year, more than one-quarter of global emissions. In 2023, China, the United States, India, the EU, Russia, Japan, and Iran together accounted for 69.7% of total global fossil emissions.
Atmospheric carbon dioxide has increased by about 50% over pre-industrial levels as of 2021. Total cumulative emissions from 1870 to 2022 were 703 gigatonnes of carbon, with fossil fuels and industry contributing 484 gigatonnes and land use change contributing 219 gigatonnes.
Energy overall is responsible for around 73% of global emissions. The power sector is the largest contributor at approximately 27%, followed by transport at 15%, with industrial energy and agriculture each at 11%. Buildings accounted for 12 gigatonnes of CO2-equivalent in 2019.
The richest 1% of the global population caused twice as much carbon emissions as the poorest 50% over the 25 years from 1990 to 2015, representing 15% of cumulative emissions versus 7%. The wealthiest 5% were responsible for 37% of the absolute increase in global emissions over that period.
The Paris Agreement aims to limit warming to 1.5 degrees Celsius above pre-industrial levels by 2030, which requires per capita emissions of 2.3 tonnes of CO2-equivalent per year. Current global average emissions are 4.9 tonnes per person per year, more than twice that threshold.