Although he cannot definitely rule out a direct effect by the pollution on the birds' metabolism of the yellow pigment, or its incorporation into their feathers, the correlation between a shortage of caterpillars and faded plumage is strong evidence of a link between pollution, diet and bird colour.

ECONOMIST: Great tits

The numbers for air pollution are several steps removed from direct measurements.

FORBES: 5 Caveats About The Autism And Air Pollution Study

The story beginning overleaf assesses the implications for marine biodiversity of transgressing planetary boundaries, due to human-induced changes to the climate system, pollution and ocean acidification, as well as more direct threats like invasive species, overfishing and habitat destruction.

UNESCO: Open Access to Scientific Information