Vergara - 1976 - Physiological and morphological adaptability of ri

44 CLINHIFE AND RICE
CLIMATE CHANGE
In part the rapid population growth may well be a biological response to the best
weather that India and the world as a whole has experienced for centuries. A
number of authors including Kalnicky (1974) and Mitchell (1974) have documented
the fact that the period 1890 to 1945 vt-"as a time of gradually rising terriperatures.
This increase in temperature averaged 0.9°C for the northern hemisphere
as a whole and was accompanied by the most benign climate the world
has experienced for at least the past 1,000 years. Beneficent climatic patterns
have encouraged man to extend his cultivated area even further into areas which
in previous centuries were not capable of providing adequate returns. Land
which should not have been put to the plow has provided modest support during
the anomalous weather patterns which persisted. particularly from about I930
to 1950.
Since 1950 weather patterns have been changing for the worse over much of
the world. Temperatures have reversed themselves and have shown the most
rapid decline ever recorded. For the northem hemisphere as a whole the decline
since 1950 had already averaged 05°C by 1970. Such a decline seems almost
insignificant when tiiewed from some perspectives, but a decrease of such
magnitude can be very important.
At Houghton Pond. Massachusetts. not far from my home. the persistence of
winter ice cover has increased from 86 days to 102 days. according to exiidence
presented by Kalnickyi (1974). In central Siberia the length of the frost-free
period has shortened considerably. and off the coast of Iceland. sea ice which
in midcenturv was a problem for about l 112 weeks a year, is now present for an
average of 4 weeks. Alexander (1974) quotes Reid Bryson, Director of the
Institute of Environmental Studies at the University‘ of Wisconsin. as saying
“There is very important climate change going on right now—if it continues
[it] will affect the whole human occupation of the earth-like a billion people
starving."
Not tinly’ are temperatures showing a marked change but the precipitation
patterns appear to be shifting as xvell. Hemispheric totals have probably not
changed. nor are they expected to. but the distribution of moisture. both spatiallv
and temporally‘. appears to be adjusting to the drop in temperature. Any}
changes in precipitation averages will be most significant in areas where historic
rainfall averages have been marginal to begin with. Increases here could be of
very great benefit but decreases could prove catastrophic.
In recent years there have been a number of incidents which individually’ have
brought hardships to millions of people the xvorld around and collectively appear
to be related to the continuing climate change. Most notable is the ongoing
drought in the African Sahel described so poignantly by Davy (1974). Untold
thousands of humans have already died and several million are in serious danger
as a result of a drought now in its 6th year. The same belt of lowered precipitation
extends across the Middle East. and has already’ begun to affect India and