Redwood Reader

Last night Nova (www.pbs.org) was about Global Dimming, the result of less sunlight reaching the ground. It tied in several threads I’ve been reading about for years, including the effects of contrails from aircraft, the albedo effect and the size of particles composing the core of the water drops.
A friend showed me a website some time ago concerned with contrails. They were convinced there was a conspiracy to save the industrialized areas of the world from high levels of UV radiation due to ozone loss from pollution. The story said planes flew over the cities in the northern hemisphere and that the exhaust created a shield that slowly floated back to the surface. They could make a permanent globe if they could cover the entire earth in a short period of time, but was an impossible task, so new shields were put in place regularly via contrail. The conspirators were the US, Canada, Russia, EU, China and Japan.
It was just another crazy story until Nova reported on people checking the three days after Sept 11 2001 when no planes flew at all over the U.S. The result was a quick drop in temperature range due to lack of clouds keeping the heat in at night, with higher day temperature and cooler nights. The change was so rapid as too seem impossible.
This matches up well with CO2 Science magazines’ (www.co2science.org) reports in the Subject Index on contrails as well as the albedo effect- the reflection of sunlight off clouds and radiating back away from earth. We begin to see that climate warming is being counteracted by less sunlight reaching the surface. In fact, temperatures are less than predicted for the levels of CO2 in the atmosphere. However, global warming is not climate change, and there are plenty of problems with this man made protection too.
The most important of these is the effect on rainfall. Nova clearly illustrated normal raindrop formation with a natural nucleus. We can imagine this as some of the solid nucleus gases emitted by trees- large natural particles called aerosols. As the water condenses on the core it gains weight until it falls. The problem with man-made particulates is their size. The small cores collect water much more slowly and remain light, which can allow moisture to stay in the cloud cover far longer and bring uncertain rainfall, or cause it to fall far down wind of the normal pattern. The longer life of the clouds means even less sunlight is reaching the surface. An interesting note is that greenhouse gases really took off when we began to focus on particulates, solving one at the expense of the other.
Another effect is the rate of evaporation. Surprisingly, temperature has little to do with the rate of evaporation. Evaporation is caused by sunlight (photons) hitting the surface of the water and knocking water molecules free from the liquid environment. The wind also does this. Ice can and does evaporate. Thus evaporation is slowed whenever there is less light available. With something like 30% less light than a few decades ago, we should be seeing more clouds and cloudier days but less rainfall, or rainfall carried further before precipitating. This is climate change without warming.
CO2 Science also has several articles about the effects of long term CO2 on ecosystem nitrogen availability. Here we wish we could get the climate guys to read the plant physiokogists who have found increased CO2 leads to greater growth of nitrogen fixing bacteria, keeping higher than natural amounts of nitrogen available for extra growth. Hidden here is the fact that the protein part of glomalin requires nitrogen for sequestering carbon, and that glomalin production goes way up under increased CO2, and I haven’t heard of glomalin not forming from lack of nutrients. I have heard that fertilizing reduces the amount and effectiveness of mycorhizzia because there is no need to forage through the soil for life support.
Global dimming shows us all the data is not in yet regarding rising CO2 and global warming. We have to wonder if there is a productivity drop off due to less sunlight, and what effects that may have on agriculture and ecosystem health around the world.