Climate models and the latest IPCC data reveal four possible futures for global population, economy and environment at the end of this century.
It is important to stress that these are just four of the many possible scenarios and ways to cut emissions. But we feel the value of the exercise is in showing how much of the outcome is still in our hands and down to the choices and trade-offs we make as individuals and as society as a whole.
1: Geoengineered safety
Population 9 billion
Global energy use 8 × 1020 joules
CO2 concentration 400 ppm, dropping
We acted early in the 21st century, invested aggressively in renewable energies and crucially, geoengineering
It wasn't easy, but by investing heavily in R&D, we have built systems for sucking carbon dioxide out of the atmosphere and storing it underground. At the same time, we have invested in renewable energies and virtually weaned ourselves off fossil fuels. The net result: annual carbon emissions have plummeted, and atmospheric concentrations of CO2 are finally dropping.
Crucial to making this happen was the spread of bioenergy power plants coupled to carbon storage facilities – a soft form of geoengineering. We grew trees and plants to burn and produce electricity. They suck CO2 out of the atmosphere as they grow. We captured the greenhouse gases produced when we burn trees, and put the gases in geological seams deep underground – where they will stay for centuries or more.
Global temperatures have held steady since 2050. We've also halted the decline of sea ice in the Arctic and slowed ocean acidification. Sea levels are still rising, though, because of heat stored in the system from earlier emissions.
Via Flora Moon