Chemists have analyzed the isotopic composition of nitrous oxide – a greenhouse and ozone-destroying gas – in air samples from as far back as 1940 and found the fingerprint of nitrogen-based fertilizer. This fingerprint proves definitively that the 20 percent increase in atmospheric nitrogen since the Industrial Revolution is largely due to the Green Revolution, when use of synthetic fertilizers ramped up.

The Earth’s crust beneath the Mississippi Delta sinks at a much slower rate than what had been assumed. The researchers arrived at their conclusions by comparing detailed sea-level reconstructions from different portions of coastal Louisiana.

A series of global warming events called hyperthermals that occurred more than 50 million years ago had a similar origin to a much larger hyperthermal of the period, the Pelaeocene-Eocene Thermal Maximum (PETM), new research has found. The findings represent a breakthrough in understanding the major “burp” of carbon, equivalent to burning the entire reservoir of fossil fuels on Earth, that occurred during the PETM. The work confirms that the PETM was not a unique event – the result, perhaps, of a meteorite strike – but a natural part of Earth’s carbon cycle.