Kind of a companion post to the one on Greenland sea ice extent. This study focuses on a climate factor I have noted before–the amount of cloud cover. As cloud cover increases, some solar radiation is reflected back to higher layers of the atmosphere and space and more of the radiation that reaches the surface and is reflected, is absorbed by those clouds. If cloud cover decreases, more solar radiation reaches the surface, likely warming both land and oceans, but less of what is reflected from the Earth’s surface is absorbed by the decreased cloud cover. Cloud cover appears to vary in natural cycles; it always has and always will, but ironically, some human factors may also affect it, largely by the injection of aerosols into the atmosphere. The aerosols appear to aid cloud formation. The reduction of pollution in recent decades has meant far fewer aerosols are put in the air, and that probably has been a factor in reduced cloud cover.
A new article examines trends in cloud cover, and consequently “albedo” or reflectivity in earth’s atmosphere. There is also albedo in the form of ice and snow cover, which also tends to vary on a natural cycle, although the climate hysterics would have you believe any decline is human caused, and they will ignore increases. It appears that while there is some human contribution to the recent cloud changes via the reduction in aerosols, the variation is largely natural as it appears to have occurred in cycles over time. In any event, snow and ice cover is another factor in reflectivity and that, as discussed in an earlier post, may be increasing, which would at least partially offset any change from cloud cover. (ER Letters Article)
