  Civilization produces knowledge, which acts as the driving force of its
development. A macro-model of civilization that accounts for the effect of
knowledge production on population, energy consumption and environmental
conditions is developed. The model includes dynamic equations for world
population, amount of knowledge circulating in civilization, the share of
fossil fuels in total energy consumption, atmospheric CO2 concentration, and
global mean surface temperature. Energy dissipation in knowledge production and
direct loss of knowledge are taken into account. The model is calibrated using
historical data for each variable. About 90 scenarios were calculated. It was
shown that there are two control parameters - sensitivity of the population to
temperature rise and coefficient of knowledge loss - which determine the future
of civilization. In the two-dimensional space of these parameters, there is an
area of sustainable development and an area of loss of stability. Calculations
show that civilization is located just on the critical curve separating these
areas, that is, at the edge of stability. A small deviation can ultimately lead
either to a steady state of 10+ billion people or to the complete extinction of
civilization. There are no intermediate steady states.
