The  environment  of  the  Earth  is










the  world's  continental  shelves  were










for  ever  changing.    Changes  occur  at










alternately exposed and flooded.










a  whole  array  of  time  scales  and,  for










All these natural changes have had a










example,  over  geological  time,  the










major impact on the fortunes of human










Earth  has  witnessed  both  greenhouse










societies and have played a role in such










and  icehouse  conditions.  Even  over










matters  as  migrations,  the  collapse










the last few millions of years,  we have










of  civilizations,  and  the  origins  of










experienced repeated lurches from glacial










agriculture.










to  interglacial  conditions,  while  over










Now, however, humans are having an










the last ten thousand or so years of the










increasingly important role in promoting










Holocene    we  have  had  neoglaciations










environmental change.  On the one hand,










(such as the Little Ice Age), pluvials in










changes in land cover are modifying rates










the  Sahara,  and  several    phases  when










of erosion and runoff , while on the other










conditions have been warmer than today










the emission of a cocktail of greenhouse










(as in early Medieval times).  At a shorter










gases into the atmosphere is starting to










time scale  there have been fluctuations










cause global climate change.  In coming










at  the  decadal  scale,  including  ENSO,










decades  it  is  likely  that,  for  example,










the Pacific Decadal Oscillation, and the










many  glaciers  will  melt,  permafrost










North Atlantic Oscillation.  In addition to










will  decay,  sea  levels will  rise,  rainfall










appreciating that there have been changes










regimes may become more extreme, and










at a whole range of scales, it is important










desert  dunes may  become  more  active.










to recognize that some changes have been










Hazards such as droughts and floods may










abrupt and also that the degree of change










change in intensity.










has  sometimes  been  very  substantial.










Environmental changes, both natural










For  example,  around  9000  years  ago,










and anthropogenic, and in  the past and










much of the currently hyperarid Sahara










in  the future, are now a major concern










was a savanna landscape with large lakes










for  many  academic  disciplines,  and  so










and some major  rivers.   Conversely,  at










the  appearance  of  this  new  journal  is










the maximum of the last glacial, around










extremely timely and significant.










20,  000  years  ago,  many  parts  of  the










currently  humid  tropics  were  probably










Andrew Goudie, University of Oxford, UK.