Global Dimming
Last Tuesday, the public television program Nova was an episode titled "Global Dimming." It was about the fact that sunlight reaching the Earth's surface has been getting less and less over the past decades. If I heard correctly, sunlight at the Earth's surface is as much as 30 percent less than what it was some forty or fifty years ago. While I have been passively aware of this decline in sunlight, and understand why, having it brought to my attention through the show was powerful, especially the ending implication of this physical change, which is rather scary.
Global dimming (global because it has been measured everywhere) is due to human activity, particularly the burning of fossil fuels and our industrial activity, which is injecting minute particles into the atmosphere. These particles in turn block sunlight, primarily in their functioning as the catalyst for cloud formation. You see, for clouds to form, particles are needed for water droplets to adhere to. The more particles, the greater extent of cloud cover. The more clouds, the more they both block sunlight and also function as a reflector, sending sunlight back out into space before it reaches the ground.
A second way that humans have changed the cloud cover is by our extensive flying of jet airplanes. Besides injecting particles from their exhaust directly into the upper atmosphere, they cause instant cooling of air as they pass through, creating visible contrails, which are human made clouds. These contrails can be rather extensive in their own right as cloud cover.
Now here is the scary part that really got me sitting forward as I watched the show: This human induced solar dimming, which is cooling the surface of the Earth, may in fact be masking the full effect of global warming. In other words, if we hadn't been cooling the Earthy through this dimming, the increase of temperature already measured as higher might in fact be higher still. And if we do the right thing in "fixing" solar dimming by reducing our pollution and injection of particles into the atmosphere, we'd actually bring on further global warming.
Simply put, we are stuck between a rock and a hard place. We are dammed if we do, dammed if we don't. Throughout the industrial era we've been changing the atmosphere, both through global dimming and global warming from the injecting of both physical particles and greenhouse energy-absorbing gases. Yet to fix either one will make things worse, and the solution to fix one may be counterproductive in fixing the other.
A very strong ethical and moral dilemma. Not easily answered.
My initial inclination: We shouldn't be tinkering with the atmosphere, which our extensive industrialization and excess population has done. We have to stop. And yes, this could unleash worse global warming. But we need to get through this time ahead as quickly as we can to get to the time beyond, when the Earth won't be so harmed.
Pondering in Dubuque....
Global dimming (global because it has been measured everywhere) is due to human activity, particularly the burning of fossil fuels and our industrial activity, which is injecting minute particles into the atmosphere. These particles in turn block sunlight, primarily in their functioning as the catalyst for cloud formation. You see, for clouds to form, particles are needed for water droplets to adhere to. The more particles, the greater extent of cloud cover. The more clouds, the more they both block sunlight and also function as a reflector, sending sunlight back out into space before it reaches the ground.
A second way that humans have changed the cloud cover is by our extensive flying of jet airplanes. Besides injecting particles from their exhaust directly into the upper atmosphere, they cause instant cooling of air as they pass through, creating visible contrails, which are human made clouds. These contrails can be rather extensive in their own right as cloud cover.
Now here is the scary part that really got me sitting forward as I watched the show: This human induced solar dimming, which is cooling the surface of the Earth, may in fact be masking the full effect of global warming. In other words, if we hadn't been cooling the Earthy through this dimming, the increase of temperature already measured as higher might in fact be higher still. And if we do the right thing in "fixing" solar dimming by reducing our pollution and injection of particles into the atmosphere, we'd actually bring on further global warming.
Simply put, we are stuck between a rock and a hard place. We are dammed if we do, dammed if we don't. Throughout the industrial era we've been changing the atmosphere, both through global dimming and global warming from the injecting of both physical particles and greenhouse energy-absorbing gases. Yet to fix either one will make things worse, and the solution to fix one may be counterproductive in fixing the other.
A very strong ethical and moral dilemma. Not easily answered.
My initial inclination: We shouldn't be tinkering with the atmosphere, which our extensive industrialization and excess population has done. We have to stop. And yes, this could unleash worse global warming. But we need to get through this time ahead as quickly as we can to get to the time beyond, when the Earth won't be so harmed.
Pondering in Dubuque....
posted by Kevin Anderson K9IUA at 6:23 PM
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