Some scientists have proposed reducing the effects of a warming climate by using engineering approaches to combat the effects of increased greenhouse gas concentrations.  These approaches include planting more forests, fertilizing the ocean to increase the uptake of carbon through algae growth, and space mirrors to redirect solar energy away from the earth.   But how effect are these approaches likely to be?  A new research study published in Nature magazine discusses the results of a computer modeling study which calculates the relative effects of using each of these geoengineering approaches to reduce global warming.  You can read the article by clicking here.  Unfortunately, even when these methods are used continuously over 50 years at reasonably large scales, warming is reduced by only about 8 percent or have unacceptably severe side effects.  This indicates that engineering attempts to reduce global warming may have very limited effectiveness.