While the melting of the ice requires heat, and therefore temporarily cools the planet, it has the reverse effect in the long run, because ice and snow reflect more radiation back to space than does water. The reflection coefficient, the Bond albedo, says 29% of solar radiation received is scattered back into space, but as ice melts, that number drops.
Water serves as the natural temperature controller of the planet, but this thermostat can only increase its cooling effect so long as there is ice at the glaciers and the poles. Once the ice is gone, the temperature will jump because incoming solar energy will be absorbed by the melting ice, and therefore, besides providing the energy needed to support life on Earth, the excess heat coming from the sun has to increase the temperature of the planet itself. While the overall planet warms, there will also be localized cooling caused by the stopping of ocean currents, such as the Gulf Current, which is a gigantic heat conveyor, moving the heat from the Equator to Europe and the east coast of the United States.
The heat input of the planet is received from the sun and is a variable. Over the past few hundred years, there has been a steady increase in the numbers of sunspots and the Earth's temperature has also increased in proportion to them by about 0.2˚C. On the other hand, as shown by the figure to the right, during the last half century this process reversed, solar activity was dropping while the temperature of the planet increased (Figure 2).
For the dynamics of the atmospheric heat balance process, we have fairly good historical data concerning the dynamics and effects of hurricanes, wind, rain, clouds, CO2 content, smoke, etc. The energy content of a larger hurricane approaches the energy consumption of the United States for about a year and serves to equalize the air temperature in the stratosphere. As far as the dynamics of the thermal processes on the continents and in the oceans goes, the inertia and time constants of the process are much greater and take much more energy to move or reverse.
So what are the variables (the control valves if you wish) that can influence the operation of this heat transfer control loop? What can humans manipulate (accidentally or intentionally) to lower and stabilize the global temperature?
- Lower the amount of the incoming solar heat by introducing large quantities of solids into the atmosphere to block the sun's radiation. This can occur due to natural causes such as nuclear wars, large fires or volcanic activity.
- Change the reflectivity of the planet's surface by making roofs and road surfaces more reflective (lighter in color).
- Rebalance animal and plant life by the introduction of gigantic algae farms in the oceans or by other means.
• Lower the CO2 concentration of the atmosphere by gradually replacing fossil fuels with solar-hydrogen and other renewable energy sources.
It seems that the simplest variable to manipulate is to gradually stop the burning of fossil fuels. This we can do voluntarily and in a planned manner on the time frame dictated by the process control model, or we can let nature do it for us as fossil fuels are exhausted. The consequences of the second can be drastic and can possibly cause the collapse of human civilization (turn the process into a batch one).