Atmospheric methane concentration plateaued leading up to 2006, but began to rise again in 2007. The source of the increase has been widely debated, but using satellite imagery a recent study has found that the increase can be ascribed to increased fossil fuels and livestock sources in roughly equal measure.
A recent study, published in Nature, reports on how anonymized data from three quarter of a million global smart phones was used to detect and map physical inactivity around the world. The study is an outstanding example of the type of scientific analyses that is possible using human beings as sensors.
It is known that orbital forcing is involved in glacial/deglacial cycles but is insufficient by itself to explain the glacial/deglacial cycles. This study argues that a biological feedback mechanism kicks in when a threshold is reached and together with orbital forcing results in the sustained and rapidly increasing CO2 and surface temperature of a deglaciation.
New evidence from analyzing fossil plankton shells has revealed that CO2 concentration in the Earth’s atmosphere was about triple current levels around 52 million years ago. It then declined to levels close to current atmospheric CO2 concentration 34 million years ago when Antarctica began to glaciate.