"Climate Restoration… we already have the means to achieve this goal and as the scientific community focuses more on this goal, others will emerge."
BCL co-founder Peter Fiekowsky in Forbes, October 3, 2017
What kind of climate do we want?
Earth’s climate system is in an alarming state. And no matter what we do in the short term, it will for a while march unstoppably—and with increasing speed—into increasingly catastrophic territory. Even halting all GHG emissions tomorrow wouldn’t change that fact.
Unless that future climate is the legacy we want to leave our children, we need to do more than cut emissions: we must also rapidly remove carbon dioxide from the atmosphere.
This begs the question, “How much CO2 should we remove?” A sensible science-based answer is to remove enough to return the atmosphere to pre-industrial conditions (at or below 280 ppm). Reducing atmospheric CO2 to such levels means returning to the climate that cradled the development of human civilization. It means returning to a “Healthy Climate” and that is what we mean by Climate Restoration.
The data behind this chart comes from bubbles of air trapped in glacial ice cores. These ancient air samples tell us that for hundreds of thousands of years, CO2 levels have fluctuated from 200 ppm (during ice ages) to 280 ppm (at the height of warmer interglacial periods). The last time they reached 300 ppm (the grey line) was over 325,000 years ago. The last time they reached today’s levels of over 400 ppm was during the Pliocene, three to five million years ago. At that time, sea levels were 16 to 131 feet higher than today. Global temperatures averaged 5.4 to 7.2 degrees Fahrenheit) warmer and the North and South poles were as much as 10 degrees Celsius (18 degrees Fahrenheit) hotter than today.
How do we get to a Healthy Climate?
The menu of climate restoration strategies is growing quickly, as recognition of the essential need to restore the climate spurs human ingenuity globally. None of these options are perfect, but potentially, together, they may form the silver buckshot we need.
Carbon Dioxide Removal (CDR) is a foundational technology of climate restoration. The following kinds of CDR offer a variety of strategies.
Direct Air Capture (DAC) is the process of capturing CO2 from the air so it can be converted to stable forms. Captured CO2 can be converted into commercially viable limestone aggregate for concrete for roads and buildings. Captured CO2 can also be buried in basalt rock fields, which are common worldwide.
Here are strategies that work with earth’s biological systems to remove CO2:
- In Biochar plants capture CO2 and the plants are converted by pyrolysis to a coal-like form that effectively sequesters the CO2. Additionally, the conversion can also produce syngas and bio-oil.
- BECCS stands for Bio-Energy with Carbon Capture and Storage. Plant residues are burned to produce energy and the released CO2 is captured and then injected into geological formations.
- Afforestation is the establishment of a forest or stand of trees in an area where there is no previous or recent tree cover.
- Ocean iron fertilization (OIF) distributes iron dust onto the ocean, encouraging phytoplankton and therefore sequestration in planktonic carbon-based skeletons. Much of this fixed carbon becomes isolated from the atmosphere for centuries. Increasing phytoplankton also benefits many species higher up the food chain. OIF is relatively inexpensive compared to DAC.
- Marine permaculture grows kelp in deep water using floating lattice structures. Kelp hosts myriad lifeforms. Whatever is not consumed dies off and drops into the deep sea, sequestering carbon for centuries. Floating kelp forests can also provide food, feed, fertilizer, fiber, and biofuels.
Cooling the planet
Temporary cooling of our planet may be needed. Solar Radiation Management (SRM) strategies could allow us to cool the planet for a few decades while we reduce CO2 levels to pre-industrial levels. The following SRM techniques involve manipulating clouds to either increase heat loss to space, or increase reflectance of incoming solar radiation. Many questions about SRM efficacy and side effects need to be studied before deployment of such climate engineering techniques.
- Stratospheric Aerosol Injection pumps sulfates high into the stratosphere to reflect incoming solar radiation.
- Marine cloud brightening seeds clouds over the ocean with nanoparticles of salt or other materials to increase their capacity to reflect incoming solar radiation.
- In cirrus cloud thinning high cirrus clouds are thinned by seeding them with aerosols, allowing more radiant heat from the earth to escape.
These strategies and others yet to be developed can help us leave our children the kind of healthy climate we inherited from our parents. All that’s needed is the political will to get to work executing them.
More on Climate Restoration
Center for Carbon Removal: focused on "innovation to build better carbon removal solutions."
Can Carbon-Dioxide Removal Save the World? CO2 could soon reach levels that, it’s widely agreed, will lead to catastrophe. The New Yorker, November 20, 2017.
Negative-emissions technology: What they don’t tell you about climate change. Stopping the flow of carbon dioxide into the atmosphere is not enough. It has to be sucked out, too. The Economist, November 16, 2017.
Sucking up carbon: Greenhouse gases must be scrubbed from the air. Cutting emissions will not be enough to keep global warming in check. The Economist, November 16, 2017.
The Search Is on for Pulling Carbon from the Air: Scientists are investigating a range of technologies they hope can capture lots of carbon without a lot of cost. Scientific America, December 27, 2016.