We have used the majority of our carbon budget and we are already at dangerous levels of CO2 concentrations, about 400 parts per million. The levels were 250 before industrialization. So the problem is what we have done already and, therefore, what must be undone.

Geoengineering means changing the Earth's fundamental large-scale processes.

CO2 from air can replace petroleum: it can produce plastics and acetate, it can produce carbon fibers that replace metals and clean hydrocarbons, such as synthetic gasoline. We can use CO2 to desalinate water, enhance the production of vegetables and fruit in greenhouses, carbonate our beverages and produce biofertilizers that enhance the productivity of the soil without poisoning it. Carbon negative technology is absolutely needed now.

The change in economic values created by the new markets for global public goods will reorient our global economy and under the right conditions can usher the satisfaction of basic needs of the present and of the future. This is what is needed right now.

We are in the midst of the 6th largest extinction event in the history of the plant and the first caused by human action.

As difficult as it is to eliminate the risk of nuclear warfare, it requires fewer changes to the global economy than does averting or reversing climate change.

We have used the majority of our carbon budget and we are already at dangerous levels of CO2 concentrations, about 400 parts per million. The levels were 250 before industrialization. So the problem is what we have done already and, therefore, what must be undone.