Here's the trouble with emissions. They've got killer hangovers. Take DDT. Not only is it still with us, it's actually increasing in the western North Atlantic—despite 30 years of restrictions on its use.
A modelling study published in Geophysical Research Letters finds substantial quantities of the pesticide still being released from the World Ocean. And though most DDT use today occurs in the southern hemisphere, concentrations are growing in the northern hemisphere as the old stuff cycles between oceans and atmosphere.
In fact, this study's computer model, simulating DDT circulation between ocean and atmosphere from 1950 to 2002, suggests the regurgitation of old DDT from the ocean is now greater than from ongoing sources of DDT.
Plus the stuff's migrating north and has been since the 1960s. Says the paper:
"The sea region that has been representing the most significant (secondary) DDT source is the western N Atlantic (Gulf stream and N Atlantic Drift regions)."
More bad news for a heavily populated part of the world and all the marine life left in those once heavily populated waters.