Drought, excess heat, loss of irrigation from snowpacks and glaciers, and topsoil loss from drought combined with occasional torrential rainfalls have the opposite effect on plant growth.<p>For plants that aren&#x27;t protected in greenhouses, increased CO2 can make them more vulnerable to insects. This is true of soybeans, for example: <a href="http:&#x2F;&#x2F;www.sciencedaily.com&#x2F;releases&#x2F;2008&#x2F;03&#x2F;080324173612.htm" rel="nofollow">http:&#x2F;&#x2F;www.sciencedaily.com&#x2F;releases&#x2F;2008&#x2F;03&#x2F;080324173612.ht...</a>