In some cases, sunlight shines through holes in the cavern ceiling, illuminating the beautifully clear, blue-tinted water giving it an otherworldly feel.
Although he offers some points of light -- putting an aerosol layer of fine particles into the stratosphere to reflect back sunlight may, he says, could buy us some time by slowing down the rate of decline for a decade -- his projections are on the whole brutally pessimistic.