A layer of suspended aerosols, dust and pollution in the atmosphere has acted as a sunscreen of sorts, protecting Earth's surface from excessive warming due to greenhouse gases, by blocking sunlight. A study by NASA scientists has found the protective layer has been thinning since the early ’90s, stifling the layer’s ability to counteract global warming.

"When more sunlight can get through the atmosphere and warm Earth's surface, you're going to have an effect on climate and temperature," said lead author Michael Mishchenko of NASA's Goddard Institute for Space Studies

The study gives some insight into why the usual gradual decline in sunlight reaching Earth has rebounded in the last two decades. It’s estimated as of 2005 there had been a drop in aerosol levels by as much as 20 percent over a relatively stable period in the mid ’80s to early ’90s.

But what does it mean for global warming?

The findings are consistent with previous observations showing the amount of sunlight reaching Earth’s surface began to increase in the ’90s after going through a period of decline. Global dimming becoming global brightening at the same time as aerosol levels decline doesn’t create a conclusive link between the two though, because cloud cover changes couldn't be ruled out. Thinning aerosols (brightening) also isn’t known to be a big contributor to global warming because dimming can happen at the same time as warming.

I won't be waiting for conclusions

What all this means to me is a lot of confusion, and realization that if it’s hard for a global warming believer to understand the science and what it all means, it’s going to be almost impossible to use it to convince a skeptic. It seems there's still a lot we don't know about atmospheric systems, and because of that it's probably best to err on the side of caution. Even though it's good to know there are people working to study climate change and provide solutions, I don't want to wait around until they figure the science out.

And hopefully this finding won’t fuel the recent interest in solving global warming through drastic measures. Including one that would see a man-made volcano spew sulphur and potentially cool the earth, regardless of the other unknown side-effects.