The Dalai Lama endorses the 350ppm
target for atmospheric carbon dioxide
Scientific background, the letter, developments
We are challenged not only to reduce carbon gas emissions, but to actively remove huge quantities of fossil carbon already present in the atmosphere.
The best scientific evidence suggests 350ppm is the upper limit of a safe-climate zone (300–350 ppm) for human civilization. It is the only target so far proposed consistent with the avoidance of runaway global warming. The existential challenge we face is expressed as a simple target figure, first defined by NASA’s James Hansen and colleagues in a key 2008 scientific paper, Target Atmospheric CO2–Where Should Humanity Aim? which states:
If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm, but likely less than that… An initial 350 ppm CO2 target may be achievable by phasing out coal use except where CO2 is captured, and adopting agricultural and forestry practices that sequester carbon. If the present overshoot of this target CO2 is not brief, there is a possibility of seeding irreversible catastrophic effects.
At many sites around the world, such as Mauna Loa in Hawaii, scientists have measured man-made increases in the greenhouse gas carbon dioxide, the main driver of global warming. Atmospheric carbon dioxide fluctuates annually, because more is “drawn down” during summer by large Northern Hemisphere forests. The annual cycle, shown in the inset figure, appears as “saw-teeth” behind the yearly average rise.
The pre-industrial atmospheric concentration of carbon dioxide was 280 ppm. The current level is 395 ppm—the highest for 650,000 years, long before the modern human species appeared. Where should humanity aim? The safe-climate target for atmospheric carbon dioxide is 350 ppm, the level that avoids the possibility of runaway warming and maintains the planet we know.
We are honored to present here the Dalai Lama’s official letter of endorsement of the 350 ppm target. Among the growing list of other international figures supporting this target are Nobel Laureate Archbishop Desmond Tutu, Indian environmental leader Dr. Vandana Shiva, Canadian biologist and broadcaster Dr.David Suzuki, Dr.Hermann Scheer, chairman of the World Council for Renewable Energy, and Sheila Watt-Cloutier, chairperson of the Inuit Circumpolar Council. It has been endorsed in a personal capacity by Dr Rajendra Pachauri, head of the IPCC. The world's leading climate economist Sir Nicholas Stern describes it as "a very sensible long-term target"