JULIAN HUXLEY 
harmless flowers as well as so-called weeds. By killing cater- 
pillars, they have caused the virtual disappearance of many of 
our butterflies and have sadly reduced the population of 
cuckoos and various songbirds. Numbers of birds are killed 
directly by eating poisoned grain, and others rendered sterile by 
the poisoned flesh of the insects and other creatures they eat. 
Enjoyment as well as material resources are being threatened; 
as my brother Aldous said after reading Rachel Carson’s book, 
we are exterminating half the basis of English poetry! 
Scientific ecology gives the basis for good land use. I have 
already pointed out how important a proper land-use policy is 
in underdeveloped countries like Africa. It is equally important, 
though for rather other reasons, in overcrowded and highly 
developed countries like our own. In Britain, for instance, we 
have an actual shortage of space, and there is constant pressure 
on the land’s surface for a variety of different and even conflict- 
ing forms of use—for house-building, for communication, for 
industry, for military purposes, and for enjoyment. Somehow 
different forms of land use must be amicably co-ordinated, 
so that one form of use is paramount in one area, another 
in another. Proper land-use planning is applied human 
ecology. 
Biologically-minded planners must also think about long- 
term ecological changes affecting the human habitat. Thus it 
appears probable that the present interglacial and relatively 
mild climate will continue for well over 5,000 years, with con- 
sequent melting of ice-caps, raising of the absolute sea-level, and 
threatened flooding of large areas of coastal flatlands (except 
in the arctic and subarctic, where isostatic recovery will con- 
tinue to raise the land and lower the relative sea-level for about 
4,000 years); but that, on the basis of Milankovich’s and van 
Woerkom’s calculations, this will be succeeded, a little over 
10,000 years from now, by the onset of a new cold period of 
increasing glaciation. 
Man lives in three kinds of habitat, the planetary, the social 
and the psychological. The planetary habitat, the concern of 
ecology in the ordinary sense, I have just been discussing. To 
IO 
