NETs have often been considered technologies of last resort. As emissions keep rising and global carbon budgets decline, it is becoming increasingly apparent that if we are to stave off the worst of climate change we must deploy and scale these desperate remedies as quickly as possible. Atmospheric carbon is the primary cause of the climate crisis and current CO2 concentrations are now higher than they have been in at least 800,000 years. (Lindsey, 2019). The average level of atmospheric CO2 for the month of December 2019 at Mauna Loa was 411.76 ppm (National Oceanic and Atmospheric Administration [NOAA], n.d.). That means we are less than 39 ppm below what is considered to be the redline of 450 ppm (Climate Change Research Centre [CCRC], 2007). The IPCC has warned us not to allow temperatures to surpass 1.5 degrees Celsius above preindustrial norms (Intergovernmental Panel on Climate Change [IPCC], 2018), however, we are rapidly running out of time as we are already more than two-thirds of the way there. Three years ago, we recorded average temperatures that were 1.1 degrees C above preindustrial norms (World Meteorological Organization [WMO], 2017). At the current rate of greenhouse gas emissions, we are on track to exceed the upper-temperature threshold limit within 5 to 10 years.
Deploying carbon capture is a massive endeavor and we have limited time. As explained by Julio Friedmann, a senior research scholar at Columbia University’s Center for Global Energy Policy, “We have to create an industry the size of the oil and gas industry that runs in reverse. And we’re on the clock. If we could do that over 200 years, I’d be a lot more relaxed,” (Kramer, 2020). Time is a luxury we do not have. We need to quickly identify and refine the most promising research directions and implement them at scale.
We have known that we require carbon capture technologies for many years but that need has grown as our emissions continue to rise. More than a decade ago the International Energy Agency estimated that over 200 power plants need to be fitted with carbon capture and sequestration (CCS) technology by 2030, in order to prevent temperature rises of over 3°C (International Energy Agency [IEA], 2010). An IPCC report (2018) indicates that all remaining gas and coal-fired power plants need CCS technology. Carbon removal is also a core feature of UN climate action plans (IPCC, 2005; IPCC, 2018; United Nations Framework Convention on Climate Change [UNFCCC], the Paris Climate Agreement, n.d.). The IPCC (2018) suggests we will need to remove 1 trillion metric tons of carbon from the biosphere over the 21st century.
We are not doing anywhere near enough to reduce emissions. Even oil industry reports indicate that current policies fall “well short of” what’s “necessary to achieve the Paris climate goals” (BP Energy Economics, 2018). To compound the problem, new climate models suggest carbon reduction efforts to keep temperatures below 1.5 C may already be “out of reach” (Hood, 2020). University of Tasmania professor Pete Strutton suggests that drastic cuts in CO2 output will no longer be enough to prevent warming of 3 C (Global Carbon Project, [GCP], 2019). In the context of this information, negative emissions technologies (NETs) are now as important as zeroing out emissions.
The viability of NETs is buoyed by the progress we have seen in recent years. Stephen Pacala, a Princeton professor who oversaw a comprehensive 2019 study of carbon removal strategies said, “the good news is that CO2-removal technology has advanced far faster than expected in the last decade.” (Welch, 2019). Research from the Massachusetts Institute of Technology (MIT) suggests that carbon sequestering can reduce human-generated CO2 up to 80 percent of 1990 levels by 2050 (Fairley, 2009). National Academies committee member Jennifer Wilcox of Worcester Polytechnic Institute indicates the technology is viable. She said: “We have the technology today. It’s not crazy expensive and it adds up to gigatons” (Kramer, 2020). However, we need to expedite the implementation process, and for this, we need to assess the viability and scalability of existing approaches.
The importance of NETs is borne out by the plethora of warnings issued by scientists over the last half-century. Fifty years ago, climate models accurately predicted that greenhouse gases cause global warming (Hausfather et al, 2020). In 2007 the Stern Review warned us that we had to urgently reduce our emissions to avoid the worst impacts of climate change (Stern, 2007). The WRI warned that we need to stop burning coal (Yang & Cui, 2012) and the IPCC synthesis report (2014) said that we must stop using fossil fuels. In 2013 the IPCC warned us to reduce emissions (IPCC AR5, 2013). Warnings have also come from other sources including the National Climate Assessment [NCA3] (2014) AGU (Landau, 2018) the WMO (2017), and the IEA (2019) all of which have told us that we are running out of time to slash emissions. In 2017 we were warned to reduce emissions in the NCA4 (2018) and an open letter from the Alliance of World Scientists (Kayal, et al 2018). The warnings continued in 2018 including another IPCC study (2018) that urged governments to take urgent action stating we are teetering on the cusp of a man-made climate calamity. Another IPCC report (2019) warned that we are seeing accelerated ice melt and sea-level rise and more than 10,000 scientists from 153 countries declared a “climate emergency” (Ripple et al, 2019).
We have not heeded these warnings and we are rapidly exhausting our carbon budgets. Emissions have been rising since the dawn of the industrial revolution and although they flattened out between 2014 and 2016, they began to rise again in 2017 (Friedlingstein, et al. 2019). They rose in 2018, and we broke another record in 2019 (GCP, 2019).
In 2014, the IPCC (AR5, 2014) estimated the remaining carbon budget to be 118 gigatons of CO2 (GtCO2) between 2018 and 2100 if temperatures are to be kept below 1.5C. That gave us approximately three years of business-as-usual emissions. In 2018 the IPCC’s SR15 report (IPCC, 2018) raised the budget to 420GtCO2 giving us 10 years to slash emissions to have a 66 percent chance of avoiding 1.5C. The budget for a 50/50 chance of staying below 1.5C was increased to 580GtCO2 which gave us 14 years of current emissions.
The Climate Change Performance Index indicates that countries are far from the objectives laid out in the Paris Climate Agreement (Burck, et al, 2019). The 2018 Gap Report clearly stated that countries were falling behind on their emissions reduction commitments (UN Environment Programme [UNEP], 2018). The 2019 UN Gap Report suggests that we are falling even further behind (UNEP, 2019). According to the UN’s 10th Emissions Gap Report, global emissions are expected to keep climbing, putting us on track to push past dangerous upper threshold temperature limits (UNEP, 2019). A report from the Global Carbon Project, (GCP, 2019) expects that emissions from industrial activities and the burning of fossil fuels will add an estimated 36.8 billion metric tons of carbon dioxide into the atmosphere in 2019. The GCP predicted that as of the end of 2019 the total carbon emissions from all human activities, including agriculture and land use, will likely cap off at about 43.1 billion tons.
The 2018 Gap report (UNEP, 2018) warned that carbon dioxide emissions must fall by 25 percent over the next decade to keep global temperatures within 2 degrees Celsius of their preindustrial levels. To reach the more ambitious target of 1.5 C, emissions would need to fall by 55 percent. This means that we must do better than cutting emissions in half in the next decade if we are to have a 50/50 chance of staying within our carbon budget.
Twelve years from 2018 is a commonly quoted estimate of the amount of time we have to reign in emissions (IPCC, 2018). Using this estimate we have less than a decade as of January 2020. However, others including Harvard climate scientist James Anderson, think we have less than half that time (Vandette, 2019).
Rising emissions and concomitant heat will trigger feedback loops that may prove to be tipping points from which we will not be able to recover (Aengenheyster, et al, 2018). A study by Prof Jason Lowe and Dr. Dan Bernie at the UK’s Met Office Hadley Centre finds that when we factor feedback to stay “well below” 1.5C our carbon budget is estimated to be only 67GtCO2 (Lowe & Bernie, 2018).
Failure to reduce atmospheric carbon puts us on track for sea-level rise, heat, drought, and flooding that will cause widespread famine, disease, and displacement. An analysis written by an independent Melbourne, Australia think-tank called Breakthrough National Centre for Climate Restoration (BNCCR), indicates that continuing with business as usual represents a “near to mid-term existential threat to human civilization” (Spratt & Dunlop, 2019).
For references go to CDR Resources. See also Glossary of Terminology Related to CDR.Related
Carbon dioxide removal (CDR) sometimes referred to as negative emissions technology (NETs) or simply carbon removal can be divided into two major technological approaches, carbon capture (CC) and direct air...
Here is a succinct yet comprehensive primer on carbon dioxide removal (CDR)*. This short video presentation was prepared and narrated by CDR researcher Richard Matthews. After reviewing the three major...