Ecosystems and societies are changing in ways great and small and are driven by many cooccurring factors regardless of variability in climate and UV radiation.    From Wordnik.com.  [The ACIA assessment process] Reference

I'm beginning to realize that 'stop harmony' in PIE roots ie. the avoidance of both voiceless and voiced stops cooccurring in the same root might in fact undermine my initial argument against reconstructing breathy stops in PIE itself.    From Wordnik.com.  [Winter's Law in Balto-Slavic, "Hybrid Theory" and phonation - Part 2] Reference

The negative response of arctic ecosystems in the face of a shift to global climatic conditions that are apparently without precedent during the Pleistocene is likely to be considerable, particularly as their exposure to cooccurring environmental changes (i.e., enhanced levels of UV-B radiation, deposition of nitrogen compounds from the atmosphere, heavy metal and acidic pollution, radioactive contamination, increased habitat fragmentation) is also without precedent.    From Wordnik.com.  [Late-Quaternary changes in arctic terrestrial ecosystems, climate, and ultraviolet radiation levels] Reference