To get to zero CO₂ emissions, the world must convert its present fossil fuel energy economy to the zero carbon energy economy, the only one that can sustain the future of civilization.

This means conservation and renewable energy.

It does not mean carbon capture of fossil fuel energy, and it does not mean biofuels and biomass.

On the basis that the best the world can do is virtually zero CO₂-producing energy, all the published scientific research says that, to get to zero, the world also has develop the capacity to extract carbon direct from the air.

A zero CO₂ energy world is not only possible, there is every reason to think it would be a far better world than ever before. Hazel Henderson's 1988 classic The Politics of the Solar Age: An Alternative to Economics describes what that world would be like.

The lack of appreciation of this better world is probably the greatest disincentive to people pushing for real action on global climate change. Most people (including scientists) are not confident that there is any alternative to the fossil fuel economy.

All the zero carbon dioxide energy the world needs exists. Planet Earth is awash with energy. The world also has all the technology needed to make that energy available.

The fastest and easiest way to create more energy is not to use what we already have—and waste. We currently waste more energy than we use. Conservation must be considered during the development and manufacture of all products, including food.

We can...

• Use less energy, and use energy less. This means using the most energy-efficient tool or system available, or doing without.
• Use manual technologies whenever possible, with the side benefit of improving our fitness.
• Refuse. Reduce. Reuse. Recycle. Recycling must be the very last option that we consider.
• Reduce the use of concrete, steel and asphalt in construction and roads. We must also reduce the number of roads, and the number of cars that drive on them.

We have no shortage of clean energy on Earth. All the various forms of renewable energy can provide over 3,000 times the current global energy needs, before conservation is factored in.

We have at our disposal...

• solar voltaics
• solar thermal
• geothermal
• wind
• tides
• the oceans

Let's look at geothermal...

Geothermal energy will never run out as long as there is heat inside the Earth. Every house can be built with a passive geothermal heat pump, which uses differences in temperatures to cool in the summer and heat in the winter.

Active geothermal uses the heat that rises from Earth's core and puts it to use, heating water to become steam, which drives turbines that create electricity. And the heated water can then be used to heat nearby greenhouses or homes and offices.

The global geothermal resource base is larger than the resource bases of coal, oil, gas and uranium combined.

For every 100 meters of depth into the ground, the temperature of the rock increases by about 3° Celsius (5.4° F for every 328 feet of depth). Those temperature differentials can be used for passing heating and cooling.

Geothermal energy can produce electricity for between 4.5 and 7.3 cents per kilowatt-hour, which makes it competitive with new conventional fossil-fuel-fired power plants, even with their subsidies.

And ultra-deep geothermal (several miles deep) has the potential to provide heat and energy even in areas with no hot zones (volcanos, hot springs, geysers, etc.).

The only way to make renewable energy viable is to tax carbon. We need to start with a substantial tax, in the range of $100 per tonne (1,000 kilograms or 2,200 pounds), followed by increases to the $500 per tonne range.

As investors leave the conventional fuels market, they will start to invest in renewables. The only cheap fossil fuels would be those dedicated to building the renewable energy infrastructure.

At the same time, governments will need to regulate banks, so that they no longer finance destructive industries, and focus their attentions, and their funds, on renewable energies and other constructive industries.