Zero is the target

India hasn’t entirely ruled out the possibility of agreeing to a ‘net zero’ target
Zero is the target
"Ahead of the 26th meeting of the UN of (CoP) that began on November 1 in Glasgow, the focus on making the meet a success is to have all nations commit to a 'net zero'."Flickr [Creative Commons]

Just as the discovery of the digit “Zero” made India a hero in ancient times, presently it has the opportunity to become a hero once again by championing the cause for Zero emissions. Ahead of the 26th meeting of the UN of (CoP) that began on November 1 in Glasgow, the focus on making the meet a success is to have all nations commit to a 'net zero', or a year by which a country’s fossil fuel emissions would peak and at some point be neutralized by taking out excess carbon from the atmosphere.

India hasn’t entirely ruled out the possibility of agreeing to a ‘net zero’ target though it is unlikely to budge from its demands from developed nations on making good on their previous commitments, such as an annual $100 billion to developing countries for mitigating the impacts of climate change, facilitating technology transfer and putting in place a tangible market-based mechanism to activate the moribund carbon credit markets. This, however, means deep and significant cuts to fossil fuel use that could affect the development trajectory of India and other developing countries. “All options are on the platter,” a senior official who will be representing India at Glasgow told the correspondents, “but it will depend on how the negotiations will progress and whether we will be able to move ahead on getting developed countries to agree on a mechanism to honour their previous commitments.”

The two week conference is slated to consider climate change mitigation strategies informed by Integrated Assessment Models (IAMs) that increasingly rely on major deployments of Negative Emission Technologies (NETs) to achieve global climate targets. Although NETs can strongly complement emissions mitigation efforts, this dependence on the presumed future ability to deploy NETs at scale raises questions about the structural elements of IAMs that are influencing our understanding of mitigation efforts.

Model inter-comparison results underpinning the IPCC's special report on Global Warming of 1.5°C were used to explore the role that current assumptions are having on projections and the way in which emerging technologies, economic factors, innovation, and tradeoffs between negative emissions objectives and UN Sustainable Development Goals might have on future deployment of NETs. Current generation IAM scenarios widely assume we are capable of scaling up NETs over the coming 30 years to achieve negative emissions of the same order of magnitude as current global emissions (tens of gigatons of CO2/year) predominantly relying on highly land intensive NETs. While the technological potential of some of these approaches (e.g., direct air capture) is much greater than for the land-based technologies, these are seldom included in the scenarios. Alternative NETs (e.g., accelerated weathering) are generally excluded because of connections with industrial sectors or earth system processes that are not yet included in many models. In all cases, modeling results suggest that significant NET activity will be conducted in developing regions, raising concerns about tradeoffs with UN Sustainable Development Goals. These findings provide insight into how to improve treatment of NETs in IAMs to better inform international climate policy discussions.

Two important problems arise at this point. First, while it is not hard to imagine some harmonized global price on greenhouse gas emissions, it is less easy to imagine an internationally harmonized system for subsidizing the development of new technology. The institutional framework for the policies used in the IAMs should be consistent with our understanding of the costs of coordinating R&D policies in polycentric governance regimes. The second difficulty with NETs and the standard model of directed technical change is that many NETs have no value except for their contribution to lower GHG concentrations. These are not substitutes for some other way of producing goods. While R&D investment is required to bring NETs costs down, their use never becomes less dependent on the GHG price, as is the case with renewables replacing fossil fuels. The optimal price path for inducing the development and deployment of NETs may be different from the optimal price path for inducing a shift from fossil energy to renewables. It is probably not appropriate to assume, as is often done now, that a single economy-wide GHG price can induce both an optimal mitigation path and the optimal deployment of NETs.

A more comprehensive handling of NETs is beginning to emerge in the climate modeling literature (Holz et al. (2018). Deployment of bio-char, accelerated weathering, and soil carbon management, as well as DAC, BECCS, and AR in the C-ROADS and En-ROADS system dynamics models, find that more ambitious mitigation efforts are required for all 1.5°C compliant scenarios, especially those which assume limited availability of NETs in the future. Surface based NETs (e.g., BC, AR) have been reported to exhibit storage losses, which in some scenarios required gross CO2 removal to be maintained simply to offset storage losses from CO2 sequestered previously in soils (Sanderman et al, 2017). Creutzig et al. compared prospective impacts of BECCS and DAC on the energy system, providing analysis of the three IAM studies incorporating both. IAM assumptions and results for BECCS energy yields per tCO2 sequestered were compared and found to differ significantly (up to 40%) in magnitude and potentially sign direction from detailed bottom-up modeling results. The authors also found that DAC costs and energy inputs may be overstated in existing IAM studies (Cruetzig et all, 2019). Modeling a broader portfolio of NETs can increase negative emissions capacity while reducing total policy cost (Nemet et al; Rau, 2018).

We need to better understand how the economics of NETs will change with time and innovation. IAMs are, at their core, economic models that make projections about technology deployments, carbon prices and emissions (Calvin et al, 2019). While some NETs, such as AR or CBC could achieve emission reductions at costs <$100/tCO2 today, these costs are still higher than most voluntary markets. Many of the scenarios used for the IPCC 1.5°C report estimate that carbon prices will exceed the costs of NETs by midcentury. This is shown for the case of DAC, commonly assumed to be one of the more expensive NETs. While the costs of DAC ($100–600/tCO2) are higher than carbon cost projections in the models today, by midcentury the average cost of carbon is likely to near the upper bound of the DAC cost.

Reforestation entails allowing previously deforested lands to revert back to their natural states, while afforestation involves the growth of new forest lands where they did not previously exist (e.g., native grasslands). Both create a negative emissions pulse during the growth phase for new forests. Tradeoffs (e.g., land and water availability) between afforestation, bioenergy, and food will limit its deployment, but unlike other forms of NETs, we have empirical evidence about how effective afforestation activities, whichwill enable us to calibrate models to provide better projections.

The growth of biomass for BECCS, as well as for liquid fuels, in which the carbon is Storage (BECCS) is the most widely modeled NET to date and many models suggest it would require the planting of significant areas with bioenergy crops as well as major new infrastructure development in the form of power plants (Mac Dowell and Fajardy, 2017), CO2 pipelines reemitted to the atmosphere upon combustion in non-point sources (e.g., transportation), result in large water and fertilizer demands. Even though Direct Air Capture (DAC) will require less water and land use per ton of CO2 captured than BECCS and AF, these impacts may still be significant and need to be quantified. DAC would account for a significant portion of global energy demand if the large deployments envisaged by some IAMs are achieved with potential environmental impacts, especially if this energy comes from fossil fuels. DAC will entail the same issues in monitoring geologically sequestered CO2 as BECCS and post-combustion CCS of fossil fuels (Middleton et al., 2014). The land use requirements and other side effects of BECCS and AR are contributing to increasing discussion of other forms of NETs. These approaches have not generally been incorporated into IAMs more widely, and opportunities and challenges exist with modeling these approaches.

Accelerated weathering (AW) refers broadly to reaction of CO2 with mineral species (primarily calcium and magnesium silicates) to form thermodynamically favorable and chemically stable solid carbonates. AW can be performed on virgin feedstocks (like basalt or olivine rock) or on waste streams (alkaline streams such as steel slag) (Huijgen et al., 2005). AW is an example of a NET with large potential global capacity and co-benefits, but also significant potential side effects that have generally not yet been considered by the IAM community. Global potential for AW could be as high as 95 GtCO2/yr for dunite, 4.9 GtCO2/yr for basalt (Strefler et al., 2018). There is a growing body of literature focused on deploying AW on croplands, which could provide co-benefits of increased yields through enhancing soil alkalinity and structure and providing beneficial use for silicate waste materials (Beerling et al., 2018). Runoff from land application could also help offset ocean acidification (Taylor et al., 2016). The best locations for terrestrial AW are in warm and humid regions offering the potential to reduce land use stress in these regions by increasing crop yields for bioenergy and food (Kohler et al., 2010). AW also has potential for co-deployment with afforestation, reforestation, BECCS, biochar; capturing these interaction effects with IAMs could increase the total rate capacity of negative emissions while reducing costs (Kantola et al., 2017). However, large scale deployment also risks concentrating significant environmental costs associated with surface mining, as well as soil contamination with metals, and surface water alkalinity increases in these regions.

While reforestation is the most widely discussed surface-based negative emissions approach, several other forest and agricultural land management practices are lower-cost (<$10/tCO2) and also provide co-benefits in the form of improved air, water, and soil quality, and biodiversity enhancement (Griscom et al., 2017). These practices could be implemented on existing forest or agricultural lands and thus reduce land stress relative to other NETs (e.g., BECCS/AR). For forest management, accelerating regeneration of disturbed areas, extending timber rotations, and thinning to promote higher stand growth/avoid large wildfires could increase capacity of existing forest lands without significantly encroaching on other land uses. On agricultural lands, cover crops, adoption of low-till agricultural practices, conversion to perennial crops, and improved grazing land management could all result in significant atmospheric carbon removal (NRC, 2018). The combined carbon cycle and economic modeling of IAMs could allow assessment of both the direct and indirect (i.e., market-mediated) effects of such activities, although substantial parametric uncertainty could affect results. Sensitivity analysis using IAMs could help highlight uncertain parameters with a greater impact on global climate results such that research funding could be better directed at better constraining these estimates.

Our vast seas too can come to our rescue. The ocean offers near limitless potential for negative emissions even though the costs and impacts of these approaches are only beginning to be characterized (GESAMP, 2019). Some of the research activity in this space is focused on promoting coastal ecosystems to sequester carbon in soils and sediments (Macreadie et al., 2017). IAMs could highlight the opportunities to avoid further degradation of these ecosystems as a relatively low-cost climate abatement method with significant co-benefits, including climate adaptation, clean water, and biodiversity enhancement (Furukawa et al., 1997; Gacia and Duarte, 2001; Mendez and Losada, 2004; Nagelkerken et al., 2008; Barbier et al., 2011; McLeod et al., 2011; Yang et al., 2012; Mayor's Office of Recovery Resiliency, 2019). For IAMs to capture these effects, spatially explicit datasets, as well as a more detailed understanding of carbon cycle dynamics at play in these complex ecosystems is needed (Macreadie et al., 2017).

To explore technological growth outcomes across IAMs, the scientists adapted the methodology of Wilson et al. (2013) to illustrate the projected capacity growth of NETs for IAM scenarios limiting warming to 1.5°C by 2100. Assuming a logistic saturation pathway for all new technologies, Wilson et al. looked for regularities in the relationship between the extent of saturation (k) and the time (t) it takes to achieve (Wilson et al., 2013). The authors compares the historical transition to new energy technologies to the modeled energy technology transitions in IAMs. The same method was applied to NET technologies in IAMs, using data from three major model comparison scenarios included in the IAMC database, SSPx-1.9 (Rogelj et al., 2018), ADVANCE (Luderer et al., 2018), and CD-Links (McCollum et al., 2018).

The most positive sign is that a number of countries, including the UK, have made commitments to move to a net zero emissions economy. This is in response to climate science showing that in order to halt climate change, carbon emissions have to stop – reducing them is not sufficient. ‘Net zero’ means that any emissions are balanced by absorbing an equivalent amount from the atmosphere.

Austin was one of 195 cities worldwide that signed the Paris Agreement at the United Nations Conference on Climate Change, agreeing to lower greenhouse gas emissions to alleviate the worst impacts of climate change. But this is only the most recent development in a long history of climate action taken by the city. In 2007, City Council approved a resolution to make Austin a leader in the fight against climate change.

Building on that effort, in 2014 Council set a target of community-wide net-zero greenhouse gas emissions by 2050. Currently, the City is working to implement over 130 actions that will reduce greenhouse gas emissions from energy, transport, and materials and waste sources. But it’s going to take more than City action to meet the net-zero goal – everyone has to do his/her part to cut carbon.

That’s where we need help! Taking personal action isn’t hard and also comes with great benefits. In addition to reducing our carbon footprint, we’ll also save money and time, avoid traffic, reduce pollution, improve air quality, and enjoy a healthier, more active lifestyle. Individuals can contribute by stopping to buy water in plastic, incorporating walking or biking to some of our regular short-trip destinations, turning off lights and turning off devices when not using these, keeping the tyres on the car properly inflated and getting regular tune-ups, using public transport as often as possible and also car pooling, eating more of locally produced food and reducing intake of red meat, using cold water cycle fir washing clothes, setting the thermostat to 78 in summer and 67 in winter and turning off the heater and AC when not required, not idling the car engine and using the accelerator lightly, recycling the items not required by giving these to thrift shops for repurposing. This is the individual way of being a Net-Zero Hero.

Bhushan Lal Razdan, formerly of the Indian Revenue Service, retired as Director General of Income Tax (Investigation), Chandigarh.

Disclaimer: The views and opinions expressed in this article are the personal opinions of the author.

The facts, analysis, assumptions and perspective appearing in the article do not reflect the views of GK.

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