Aerosol pollution has sharply declined since the '80s, but the pollutant's effects were to cool a now-warming the earth. "You're likely to hear a chorus of dire warnings as we approach Earth Day, but there's a serious shortage few pundits are talking about: air pollution. That's right, the world is running short on air pollution, and if we continue to cut back on smoke pouring forth from industrial smokestacks, the increase in global warming could be profound."