With fierce storm after storm hitting the Caribbean and threatening our coasts this hurricane season seems to illuminate the ever more apparent effects of climate change.  While we do not have more storms than usual the intensity appears to be on the rise, i.e. more storms are reaching higher categories thus our extremes are getting more extreme [Science].  This alone calls for our attention and efforts to make changes to decrease the greenhouse effect that is warming the Earth and causing greater highs and lows but there is more to this than meets the eye.

It is clearly necessary to work to decrease emissions that are contributing to climate change but what we may unknowingly be doing is exacerbating the problem by not fully understanding the complexity of the system. Now I am not saying we should allow massive amounts of pollution, I am merely suggesting it is more complicated than the simplified version we get watching TV or the glossy greenwashed sound bytes we are so often exposed to.  Even this write up is overly simplified but such is life.  The main complication I speak of is the phenomena that is termed “global dimming.”  Just like it sounds, global dimming describes the decrease in sunlight that is actually reaching Earth’s surface.

Over the past 4 decades scientists have watched the global incoming solar radiation decrease by 12% [American Geophysical Union]. TWELVE PERCENT. That is huge! Breaking it down for each continent the drops in sunlight recorded between the 1950s and 1990s are staggering. The level dropped 9% in Antarctica, 10% over the U.S., nearly 30% 13% over Russia, and up to 60% 16% in parts of England (thanks for pointing out this misunderstanding).  With that you would expect that we should be cooling down, right?  It is logical to think if less sunlight reaches Earth the temperature would drop, just think of a cloudy day or even just standing in the shade.  It makes a significant difference but we are not cooling down, we continue to get warmer.

With this in mind it may be that global dimming is masking or delaying the potentially far more extreme effects of global warming.  Particle pollution, like ash, soot, and sulfur dioxide, in the atmosphere is believed to be the culprit for global dimming.  Just like sunlight bounces off the top of clouds, so too will it bounce off of polluting particles. The compounding factor though, is that the polluting particles apparently make the clouds themselves far more reflective. 

If we were to eliminate global dimming all together without addressing global warming the increase in temperature and extreme weather might be more significant than previously predicted.  This has been recorded with one full degree temperature change in just a few days of decreased pollution in the days following the 9/11 attacks [Nature].  This reverse effect of dimming has been has been blamed along with global warming for increasing temperatures, appropriately called global brightening [Geophysical Research Letters]. No one wants smoggy skies but it could be smog and particulates that may be shielding us from the full consequences of the greenhouse gases we pump into our air daily.  Clear blue skies are something many folks thinks of when they think of “going green” but those clear blue skies may hold more heat than we can handle.

NOVA Global Dimming Website

BBC Special on Global Dimming on YouTube:  Part 1 | Part 2 | Part 3 | Part 4

Photo by: Bradley Cornelius Groot

The bleaching of the world’s coral reefs has been an increasingly concerning mystery in recent years.  Healthy corals harbor a host of zooxanthelae, colorful algae that live symbiotically within the coral tissue providing energy to the coral.  The coral in turn provides shelter, plenty of carbon dioxide for photosynthesis, nutrients, and protection.  When the corals are “bleached” these necessary algae are expelled leaving only the shell of the coral, its white, bleached skeleton.  Scientists for years have struggled trying to identify a cause for this. Climate change is still a major contender but National Geographic just came out with an article that suggests something else, sunscreen.

“Four commonly found sunscreen ingredients can awaken dormant viruses in the symbiotic algae called zooxanthellae that live inside reef-building coral species.

The chemicals cause the viruses to replicate until their algae hosts explode, spilling viruses into the surrounding seawater, where they can infect neighboring coral communities. “

Those four ingredients are as follows:

1. Parabens
2. Cinnamate
3. Benzophenone
4. “A camphor derivative” (likely methylbenzylidene camphor)

Parabens in particular are in all sorts of other products, even our food.  If they are the culprits in this fiasco we have a lot more to worry about other than just sunscreens. With growing concern around them I suggest reading all of your product labels and seeking out companies that are paraben-free. Even some main stream companies are transitioning over to paraben-free now so it should be getting easier in the near future.

The study is not the end all be all, it is just a step in the direction of possibly understanding this phenomena. It isn’t that hard to find a sunscreen that is made with physical sunblock rather than chemical sunblocks. Look for titanium dioxide or zinc oxide on the ingredient list and avoid the ingredients listed above.  If all else fails put on a long sleeved white shirt and a giant hat.. you may look silly but you won’t get burned and you just might make a difference.

Al Gore updated his famous slide show and presented it recently at TED, this new one is quite a bit shorter. I thought it was an interesting view, check it out.