Short answers, pulled from the story.
The G20 was formally established at a G7 Finance Ministers' meeting on the 26th of September 1999, with its inaugural meeting held on the 15th-the 16th of December 1999 in Berlin. It was founded in response to a series of emerging-market debt crises in the late 1990s, including the 1997 Asian financial crisis, the 1998 Russian financial crisis, and the collapse of the US hedge fund Long-Term Capital Management in the autumn of 1998.
Canadian finance minister Paul Martin and US Treasury Secretary Larry Summers are credited as the primary architects of the G20 at the finance-minister level. German finance minister Hans Eichel also played a key role as concurrent G7 chair, and a 2004 Brookings Institution report argued the group was founded primarily at his initiative. The actual membership list was drawn up by Eichel's deputy Caio Koch-Weser and Summers's deputy Timothy Geithner.
The G20 has 21 members: Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, the United Kingdom, the United States, the European Union, and the African Union. The African Union joined as the 21st member at the 2023 summit in New Delhi, the first new addition since the group's founding in 1999.
The 19 G20 member states account for around 85% of gross world product, 75% of international trade, 56% of the global population, and 60% of the world's land area. Including the EU and the African Union, the G20 encompasses 78.9% of the global population and 83.9% of global CO2 emissions from fossil energy.
No. The G20 operates without a permanent secretariat or staff. Each year the presiding country builds a temporary secretariat that dissolves at the end of its term. In 2010, French President Nicolas Sarkozy proposed creating a permanent secretariat similar to the United Nations, with Seoul and Paris as candidate cities, but the proposal was never adopted.
The troika is a continuity mechanism in which the current G20 presidency works alongside the immediately preceding host country and the next one in line. The three together manage institutional handoffs and keep longer-running projects alive across the annual rotation. The current rotation system has been in place since 2010, when South Korea held the chair.