carbon offsets are a conscience-clearing scam. gee, what a shock.

But, but, but: Carbon offsets are, at best, "very opaque and definitely hard for the average person to understand," said Sola Zheng, an expert on aviation at the nonprofit International Council on Clean Transportation.

The quality of offsets also faces scrutiny. Doubt persists about whether offsets purchased actually reduce emissions and don’t just throw money at projects, such as planting trees or building a wind farm, that would have happened regardless.