Modern economies are unthinkable without plentiful and affordable energy supplies. The double threat of global warming and climate change makes it mandatory to look for new, non-polluting energy sources. When searching for future energy supplies we must be very much aware of the critical role that energy plays in modern economies. It is imperative that we keep in mind the immense investments and the priceless inventories that were made by previous generations when building existing energy supply infrastructures.

Electricity has become the predominant energy form used by industry, commerce, and consumers alike. Transportation is a close second with industry, commerce, and individuals virtually incapable to maintain economic activity without immediate access to affordable liquid fuels for cars, trucks, ships, trains, and airplanes.

Continuing use of fossil fuels will result in unacceptable levels of greenhouse gases in the Earth's atmosphere. We have learned that this accumulation is responsible for global warming and that it is the root cause of climate change and its many incarnations. The world does not have a choice any longer. We must completely halt carbon dioxide emissions before the year 2050 or the world will have to deal with escalating and uncontrollable climate changes.

The costs of dealing with climate change can potentially overpower world economies, can inflict extreme suffering on most of the world's peoples, and can eventually lead to a worldwide economic collapse. Such a collapse will be the precursor of the disappearance of our civilizations.

Changing over from polluting fossil fuels to clean, new energy sources will be expensive. Trying to replace well performing industry segments would not only be foolish; it could be suicidal. We cannot dare to slow the world's economies. Economies must be highly productive when we attempt to halt all fossil fuel combustion and begin instead to use only clean, renewable energy sources. The changeover will create much additional economic activity, which can result in an overall positive effect on world economies during the next two generations.

In our efforts to change to new energy sources we must try to modify rather than replace existing energy consuming, energy converting, and energy distributing systems. We are well advised to continue the use of existing electricity generating plants, electricity transmission grids, petroleum refining plants, gasoline and diesel fuel distribution systems, inventories of cars, trucks, ships, trains, railways, airplanes, and airports. We must continue to use our manufacturing plants to produce these valuable and life supporting devices and the service systems with their trained personnel to keep them running.

Replacing even a part of this infrastructure would last generations and would cost trillions upon trillions of dollars. Replacement costs will be out of reach for even the most wealthy, most industrialized, and most technologically advanced countries. We must find solutions that keep much of the existing energy infrastructures in place. We must develop new technologies, which will not overburden our economies and which will not risk economic slowdowns, recessions, or total economical collapse.

The puzzle we have to solve is very complex. There will be more than one solution. To put our task into sharp focus let us state the problem this way: How can we best preserve as much of our infrastructure as possible, stop burning fossil fuels, and replace fossil fuels by only consuming renewable and alternative energies? Most importantly, how can we stimulate and maintain economic growth concurrently?

One such practical and actionable solution is based on the complete cessation of all fossil fuel burning. There is absolutely no way that we can prevent carbon dioxide accumulation in the atmosphere by sequestering carbon dioxide for more than a few decades. Therefore, we will have to convert all our energy sources entirely to the exclusive use of solar energy, wind energy, marine energy, geothermal energy, and nuclear energy.

Fortunately, there is enough solar energy to last us forever. Nuclear fission energy will last for centuries. Geothermal energy resources are huge but will be expensive to exploit in most locations.

Continuing shortsightedness and greed are still keeping us on the march into certain disaster. This is tragic and unacceptable. We must force our governments to accept change. New technologies are available that can give us the means and the tools to not only avoid disaster but make this world a better place to live in. All we have to do is to act with foresight. Most importantly, we must subordinate the interests of the few to the wellbeing of the many. What must we do?

We must continue to use the existing inventory of energy consuming machinery and appliances. We must preserve our marvelous transportation systems that deliver unerringly the goods, foods, and all necessities for us to live and for everybody to pursue business and pleasure. We must keep the electric transmission nets and grids that cover the world. We must keep the distribution systems that deliver motor fuels to neighborhoods and to the farthest corners of the world. We must keep the power plants, our manufacturing plants, and the refineries that convert crude energy into motor fuels. We must save our buildings and our homes.

We must concentrate our intellectual efforts and our financial resources on the development of a selected, few technologies. It appears entirely feasible to develop and demonstrate these few key technologies in less than two decades. Above all, we must act very, very soon or we will leave to future generations a very hot and barren world.