A healthy climate is not always as it seems. Redkill Lodgepole Pine stand behind a field of Douglas’ Sunflower at Steamboat Lake State Park, Colorado. Less than 0.7 degree Celsius of average warming across the globe was responsible for allowing the native mountain pine beetle to kill 20 percent of western US forests between the late 1990s and 2010. The attack continues today with the addition of spruce and fir beetles to the infestation. (Photo: Bruce Melton)

We can have a healthy climate — a climate with zero warming — in our lifetimes. The message for the last 20 years has been that we have to reduce emissions drastically to prevent dangerous climate change of more than 2 degrees C (3.6 F). This strategy would have likely worked when it was first suggested, but we have delayed far too long since then. Now, even stringent emissions reductions allow our warming to at least double and likely triple before finally beginning to cool.

We must begin to reduce the load of already-emitted, long-lived carbon dioxide (CO2) climate pollution in the sky, regardless of costs. The good news is that, not only will costs be very similar to many things we do in our society today whose costs are taken for granted, but by disconnecting emissions reductions strategies from the removal of already-emitted climate pollution in our sky, we vastly simplify the myriad strategies that have been developed to avoid dangerous climate change.

Haven’t We Begun to Deal With Climate Pollution?

The Clean Power Plan, implemented by the Environmental Protection Agency (EPA) in February 2016 seeks to limit emissions to Kyoto Protocol Era levels by 2030 — 18 years later than Kyoto’s 2012 target. Meanwhile, at the UN Paris Climate Conference in 2015, President Obama committed the US to an emissions reduction of 80 percent below 2005 levels by 2050. This is 30 years behind Kyoto Phase 2 goals of 80 percent emissions reductions by 2020.

Clearly, current rules and commitments are far behind those set 20 years ago. Moreover, since the beginning of the Kyoto Era, we have emitted almost as much climate pollution as we emitted in the previous 230 years. The Clean Power Plan has been stayed by an unprecedented Supreme Court decision pending a decision in the lower courts, but will likely be upheld.

Because of the great delay in action, current US emission reduction policy — along with 80 percent commitments around the globe — would allow the concentration of CO2 in our atmosphere to rise to 440 ppm by 2050-60, and would allow the temperature to rise by anywhere from 1.6 to 2.7 degrees C, or double to triple our current warming. Under this best-case scenario of aggressive emissions reductions, global temperature still would not fall back to today’s levels for 400 to 500 years and would not fall back to preindustrial “zero warming” for thousands of years.

Is 2 Degrees C Safe?

The demarcation of the “2 degrees C” threshold for dangerous climate change — set in 1990 by the Intergovernmental Panel on Climate Change (IPCC) — was an effort to put real numbers to the concept of “dangerous climate change.” The IPCC’s 166-page document is summarized by two sentences that spell out the risks of climate change with a certain warming:

Beyond 1.0 °C may elicit rapid, unpredictable, and non-linear responses that could lead to extensive ecosystem damage…. An absolute temperature limit of 2.0°C can be viewed as an upper limit beyond which the risks of grave damage to ecosystems, and of non-linear responses, are expected to increase rapidly.

The wording of the two statements above sheds light on just how “safe” 2 degrees C actually is. In contrast to these statements from 26 years ago, current extreme events are happening with less than a degree of warming. Even the most aggressive emissions reduction strategies allow for warming that is over double what has already occurred. Plus, warming-caused feedbacks generally grow more profound with increased heat, meaning that impacts will increase faster and become more extreme relative to impacts happening already.

What Is the Safe Target?

The Paris climate talks last year — the 21st meeting of the IPCC — made the strong suggestion that we stop using 2 degrees C of warming as a description of a “safe threshold” to dangerous climate change; and it was agreed that efforts would be made to limit warming to 1.5 degrees C or less. But is this sufficient?

The IPCC has a long and significant history in the academic literature of badly underestimating the impacts of climate change. An excellent example is that as late as the 2007 IPCC report, Antarctica was not supposed to begin losing ice until after 2100. In the 2013 report, however, Antarctic ice loss is now approaching that of Greenland. Importantly, the first academic findings on Antarctic ice loss were published in 1994. The consensus process of the IPCC causes their statements to lag recently published science; in this case, by 20 years.

Meanwhile, in 2008, James Hansen, the former 32-year director of the US climate modeling agency at NASA, lowered his threshold for dangerous climate change to 300-350 ppm CO2, or about 0.5 to 1.0 degree C of warming. We are at 400 ppm today; preindustrial CO2 was 280 ppm.

The rapid increase in extreme weather events we have been experiencing could hardly be viewed as “safe.” However, other dramatic impacts are quickly making themselves apparent. Reports of the initiation of the collapse of the West Antarctic Ice Sheet (WAIS) are becoming frequent. Megafires, according to an article in National Geographic, have grown to sizes that National Forest Service Chief Tom Tidwell says would have been “unimaginable” two decades ago. NASA and Columbia University say heat extremes, such as the $12.7 billion Texas/Southern Plains drought in 2011, are made 10 to 100 times more likely with already experienced warming. This work also says that these extreme heat events, that once happened across 0.1 to 0.2 percent of the Northern Hemisphere, now happen across 10 percent of the Northern Hemisphere every year.

Prehistoric evidence of abrupt sea level rise when Earth was about as warm as it is today — about 121,000 years ago — shows that the collapse of the WAIS resulted in 6.5 to 10 feet of sea level rise in what could be as little as 10 to 24 years. After more than two decades of IPCC sea level rise estimates of about two feet in 100 years, modeling is finally beginning to approach prehistoric evidence. The challenge has been that the IPCC rely on modeling that they themselves admit is underestimated. The former modeling of only four inches from Antarctica by 2100 is now at three feet. It is important to understand that this new modeling work is in its infancy and like the IPCC, likely underestimates. The good news is that modeling has broken free of the previous constraints that so badly underestimated ice sheet collapse relative to actual prehistoric evidence.

With the latest ice sheet collapse warning in April 2016, the National Oceanic and Atmospheric Administration (NOAA) is looking forward to upcoming publication of ongoing research from multiple sources. NOAA says that because the lag in time between academic research and inclusion of that research in the scientific consensus can be as much as “ten years,” in the next few years we will see academic publication that shows 10 feet of sea level rise from Antarctica will happen in the next 50 years. This rate is far greater than the adaptability threshold of three feet per century.

With only two meters of total sea level rise (6.5 feet), 187 million people would be physically displaced. Work from the German National Science Academy says that flooding from only 1.2 meters (4 feet) of sea level rise would impact up to 310 million people and cause up to $210 trillion in damages by 2100.

The excessive heat and flooding extremes that we have already endured — as well as the unimaginable impacts from the 10 feet of sea level rise that is set to occur — have been caused by warming of 0.7 degrees C or less. That current policy and commitments allow additional warming that is more than double what we have already seen is ample evidence that current climate pollution strategy is far behind.

Zero Warming — a Primer

This brings us back to that question: How do we move forward?

Some of the tools for getting us there are widely known: efficiency increases, alternative energy, agriculture improvements, reforestation, electric cars, smart grids, DC power transmission, showering with a friend. These are all important and critically so, because of the great risk of further increasing extremes. But these tools all allow warming of double to more than triple our current level before the temperature begins to very, very slowly cool. Emissions reductions help — in that they reduce the amount of CO2 that we are releasing into the sky — but even with aggressive emissions along the lines of the greatest reductions feasible, our climate continues to warm for at least 50 years. What is needed, if we are going to leave our children a healthy climate, are tools that can immediately begin to reduce the very long-lived CO2 that is already in our sky.

Fortunately, science has advanced a bit over the past 20 years. There is now a set of technologies out there that have been proven to do the job of atmospheric carbon removal. For $21 trillion (the cost of US health care from 2000 to 2009), we could create an infrastructure that would remove 50 ppm CO2 from our sky and make a huge dent in the atmospheric loading that is causing the warming. This cost is about $200 per ton of CO2. Newer technologies hold even more exciting prospects cost-wise. The best estimates for new technologies are at $20 per ton for capture and 20 percent more for disposal. The company, Global Thermostat, in Menlo Park, California, has a full-scale industrial pilot project that uses waste heat and is reportedly capturing CO2 at $10 per ton.

Some of the new technologies are even more compelling. One new line of research shows that CO2 captured directly from the sky can be used to create carbon nanofibers, a very advanced material that could be used to build almost anything from automobiles to homes. Production costs are similar to that of aluminum and the carbon fibers have a value 1,000 times that of aluminum. There is a fuel cell technology that can capture carbon dioxide from direct fossil fuel generation emissions that does not require additional energy and actually increases the generation capacity of the energy facility.

Then there are the solar radiation management technologies (SRM), such as injecting sulfates or tiny mirror-like particles into the upper atmosphere to reflect sunlight. There is some very important work ongoing in this field of geoengineering that could be revolutionary as well. But whereas the climate pollution removal techniques described above are relatively simple, the implications of SRM are no less significant than the greenhouse gas experiment we have been implementing for centuries. Take sulfate injection, for example. This technique is often suggested to have grave acid rain consequences but the amount of sulfates used is 100 times less than what is required to create significant acid rain. Maybe more importantly, once sulfate injection ceases, impacts to the atmosphere are completely gone after two years or less. The bottom line, however, is that atmospheric geoengineering is little studied and fraught with challenges, and far more work needs to be done before implementation is seriously considered.

The Next Steps to a Healthy Climate

We need to give ourselves permission to go beyond emissions reductions alone and seek a healthy zero-warming climate. A group of dedicated academics and climate science outreach specialists are doing just that. The Healthy Climate Project is the first to approach the issue of a zero-warming healthy climate.

What we can do as individuals is vitally important because policy grows from public will. Discuss healthy climate goals with your peers. Mainstream the concept. We need to fund development and increased research for even more compelling technologies than already exist, build a safety monitoring organization (like the Food and Drug Administration, but for carbon removal), and scale up these technologies.

The Healthy Climate Project is the first of its kind. Its “Declaration” asks President Obama to authorize research to complete the industrialization of new atmospheric CO2 removal and storage technology and commit to a healthy climate for America.

We have the tools. Now we need to allow ourselves to go beyond emissions reductions alone, in order to leave our children a planet free from dangerous climate change.

Note: Detailed references for the claims in this article can be found here.