The Science
The Science

“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 [current levels] to at most 350 ppm.”
Dr. James Hansen

Visit’s explanation of the science of 350ppm. Then…..see why we established:



To protect our world from devastating climate disruption, science tells us we must stop global warming in its tracks, and justice demands it.  This means holding total warming to the peak seen since the last ice age, just a little over 1°C (rather than the 2°C often cited), with no more than 0.4° C additional warming above what we’ve already experienced. Holding this line entails reducing atmospheric carbon dioxide levels to 350 parts per million or less, the point at which the planet stops accumulating solar heat, by 2100.  This requires annual carbon pollution reductions of just over 6% beginning immediately; it will require 15% annual reductions if we wait until 2020.

We recognize the huge challenge of reaching such goals.  But it is critical that we achieve the deepest and most sustained carbon pollution reductions now within our reach.  We acknowledge, even as we work for measures that only achieve part of this goal, they alone will not be enough. Therefore, we commit to advocating for the level of carbon reductions required by science, as well as for the comprehensive solutions needed to achieve these reductions regionally and beyond.  We must move to rapidly phase out fossil fuels by 2050 or sooner through renewable energy and energy efficiency.  Growth in land-based carbon storage is also needed, and can help make up for shortfalls in early years.

We understand that the urgency of the moment has a gift in it. By joining together to realize the opportunity of a low-carbon economy, we can restore a just and vibrant world and leave the legacy of a stable planet to our children. To this we commit ourselves.



350 Seattle has adopted the above Commitment to Science-Based Carbon Reductions and Solutions, detailing our commitment to working towards what physics demands of us if we hope to avoid catastrophic climate change.

The Commitment is based on the work of Dr. James Hansen and his team, and has been approved by Dr. Hansen.  Recently, he issued a new study that indicates that not achieving these goals may result in a 10-foot sea level rise in as little as 50 years. That would leave significant areas of Seattle inundated including a wide swathe of the Rainier Valley, as this map shows.

It has never been more important to advocate for aggressive carbon reduction goals, but our leaders are falling short. Governor Jay Inslee has recently ordered the Washington Department of Ecology to undertake regulatory rulemaking to set a binding carbon cap…but he has only asked for implementation of goals set in 2008, and current science reveals those goals to be deeply inadequate. In the year-long rule making process, 350 Seattle will be fighting for goals that integrate our ever-growing understanding of the quickly-changing climate.

President Obama’s new Clean Power Plan is similarly problematic.

If we’re serious about leaving a world for our children that is not wracked by climate chaos, we have no choice but to work for the goals that science tells us will be effective.

350 Seattle is asking other groups to sign on to the statement. If you are interested in learning more or having the statement presented to your group, please contact Patrick Mazza.

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