Indonesia is now the world's biggest source of wildfire emissions

Europe's satellites have been adding up Indonesia's smoke, and the total is now larger than any other country's. The European Union runs a monitoring service called Copernicus that estimates how much carbon fires push into the air, using the heat that satellites can see from orbit. Between 1 and 7 September, fires in Indonesia released 19.7 million tonnes of emissions, more than Russia and over a third of the world's total from fires that week. The South China Morning Post reports it is the most intense fire season in 11 years.

The size of the country does not explain it. Measured per square kilometre of land, Indonesia's fires released more than 1,500 kg, over ten times Russia's rate, and 273 per cent above the average for this point in the year. The dryness comes from El Nino, a warming of the Pacific Ocean that pulls rain away from Indonesia for months at a time. "With El Nino, it clearly just gives a big enhancement to them. It's much drier, it's hotter," said Mark Parrington, a senior scientist at the Copernicus atmosphere monitoring service. Most of the burning is in Kalimantan and eastern Sumatra.

The comparison that should worry people is 2015. In the same week of that year, the year Indonesians still remember as the worst haze crisis, fires released 21.7 million tonnes. This season is running only slightly behind that pace, and the dry months are not over. In Pontianak, in West Kalimantan, the air quality index reached 394, where anything above 300 is officially hazardous.

Why it matters

If you live in Kalimantan or eastern Sumatra, the useful part of this data is the comparison, not the tonnage: the season is tracking close to 2015 and it is only early September. Check your city's index each morning rather than judging by how thick the sky looks, and keep a proper mask for the days it climbs past 300. For Jakarta, being the world's top source of fire emissions is a number other governments can now quote back, and it arrives while ministers are already answering to Malaysia for smoke that crossed the border.