No policy tool will ever replace the good old hunch, and an Austrian
atmospheric chemist recently had a good one while observing the composition
of rainwater.

Noticing a substance produced normally by certain bacteria,
the scientist rounded up a couple of limnologists (lake scientists) and the
team set off for two months research 10,000 ft high in the Alps looking for
life in the clouds. To everyone’s surprise including their own, they found
it. Working from a frequently cloud-wrapped meteorological station whose
unusual characteristic is to be powered by electricity, thus avoiding any
atmospheric contaminants, the team collected sample droplets from cloud
cover as well as snowflakes, freezing them immediately to avoid

Results of testing showed an average of 1500 bacteria per
cubic centimeter of cloud water, not very much compared to the 10,000 to 10
million found in lakes and oceans but 1500 more than anyone had previously
imagined to exist in clouds. The lake specialists put it this way for their
atmospheric colleagues: “clouds are an immense but shallow lake, only 50
centimeters of water deep but covering two-thirds of the globe. And this
lake is inhabited”.

This omnipresence would suggest an important role for
cloud bacteria in the global climate system. Cloud water’s pH is suitable
for bacterial life, and enough organic components or pollutants to nourish
a permanent population. DNA and amino acid traces found in the sample
droplets confirm that bacteria reproduce in the clouds, and are not simply
earthlings borne by the wind.

Many questions remain: Are the cloud bacteria
a separate species or the same as found in lakes and on vegetation? What is
their effect on climate? What are the details of their life cycle and
activity in the clouds? Will this discovery prove helpful in answering the
mystery of why there is more ozone at 6 miles of altitude than predicted by
mathematical modeling?

(Le Figaro, March 9, p25, Yves Miserey)