The world is spending half a trillion dollars on fossil fuel subsidies every year, according to a new report. The Overseas Development Institute (ODI) says rich countries are spending seven times more supporting coal, oil and gas than they are on helping poorer nations fight climate change. Fuel subsidies to US farmers amounted to $1bn in 2011 says the ODI. Some countries including Egypt, Morocco and Pakistan, have subsidies bigger than the national fiscal deficit. The new report calls on the G20 to phase out the payments by 2020. While there is no globally agreed definition of what a fossil fuel subsidy actually is, the report draws on a range of sources from the International Monetary Fund to the International Energy Agency. It details the range of financial help given to oil, coal and gas producers and consumers from national governments and through international development. What emerges is a complicated web of different types of payments in different countries. In the United States, for example, the government in 2011 gave a $1bn fuel tax exemption to farmers, $1bn for the strategic petroleum reserve and $0.5bn for oil, coal and gas research and development. Germany gave financial assistance totalling 1.9bn euro to the hard coal sector in the same year. And the UK gave tax concessions worth £280m in 2011 for oil and gas production. Pakistan is a country with the second highest number of children out of school in the world. It has some of the worst nutrition, maternal mortality and child health indicators.

There have been a few times in the history of mankind when we nearly died out as a species. Anthropologists call these events “bottlenecks”, times when the population of humans shrank – perhaps to as few as 2,000 people over 50,000 years ago. At those levels, we would be categorised as an endangered species on the IUCN Red List, existing in even fewer numbers than wild tigers do today. We survived, and in fact we’ve thrived, mainly because we adapted our environment to suit our needs. But to what degree has the survival and triumph of our species changed our planet? The best people to answer this could well be those who have the grandest perspective. Geologists can take a 4.5-billion-year step back and look at the human impact on our planet in the context of its long history – they can identify changes in the rock record within layers of deposited sediments that build up and are compressed over time.