Now we might be in urgent conditions. We notice, whether we like it or not, detoriolated natural environments or anomalous weathers. Nature does not seem to be in harmony with human activities. Extended and multiplied human activities might demand the earth far beyond she could offer.
High productivity in industry and agriculture in the advanced countries is resulted from spending energy from fossil fuels available in low cost. But CO2 gas emitted in burning fossil fuels is now accumulating in atmosphere, whose outcome is greenhouse effect and acid rain. Human history tells us, however, that we experienced getting over several crises at the brink of disturbing the stable equilibrium in nature with technology and wisdom.
