Solar Radiation Management Geoengineering and Climate Change: Implications for Latin America

Solar Radiation Management Geoengineering and Climate Change: Implications for Latin America In brief Policy This briefing explores the background potential consequences of The UN Convention on using Solar Radiation Biological Diversity (CBD) Management (SRM) – a adopted a de facto form of geoengineering moratorium on being considered by some geoengineering activities in governments to address 2010 (decision X/33 (w)), climate change. SRM is a set based on the precautionary of technologies designed to approach. The decision reduce sunlight and lower requests that governments temperatures. These do not allow geoengineering technologies are currently activities to take place only theoretical, but by using Natural and proposed artificial stratospheric aerosol injection because of the potential models, scientists have been to reflect more sunlight back into space. (CC) Wikimedia Commons impacts on biodiversity and able to look at potential associated livelihoods. impacts. They have found that while some countries in temperate zones would most likely benefit In 2015, the Paris Agreement (PA) set a goal from SRM, other regions would be adversely Given the to keep global average temperature rise well affected. below 2oC by the end of the century. The important social, Agreement did not establish binding This briefing considers the climate agricultural and economic regulations to ensure the reduction of impacts for Latin America, where the consequences suggested by the greenhouse gas (GHG) emissions. So, models suggest major changes in to avoid mitigation at the scale precipitation patterns would models, and the likely risks to needed to comply with the PA goal, exacerbate dry conditions and biodiversity, we argue that some governments in high emitting increase the possibility of droughts in governments should strengthen countries are considering large regions. their precautionary geoengineering as a technological fix to Little is known about the impacts of approach and consider a lower temperatures or remove geoengineering on biodiversity and ban on SRM. greenhouse gases from the atmosphere. ecosystems, but the impacts of rapidly ending SRM experiments were found to pose a potentially acute threat to species. The resulting rapid changes in Research and text by Alejandra Straffon temperature could increase the probability of local Edited by Helen Burley extinctions in some of the most biodiverse regions on Earth. November 2018 Given the important social, agricultural and economic consequences suggested by the models, and the likely risks to biodiversity, we argue that governments should strengthen their precautionary approach and consider a ban on SRM. www.etcgroup.org Box 1 Findings Terminology: Geoengineering is the deliberate Since 2014, the scientific community has developed computational models (Earth large-scale technological System Models, or ESMs) that can assess the impact that geoengineering has at manipulation of Earth systems (in the both regional and global levels. Ten different models have been used to examine stratosphere, in the ocean, or in the how SRM could reduce radiative forcing from the sun (see for example Yu, et al., ground) to try to affect the climate. 2015). This can include Solar Radiation These studies agree that SRM could lead to a decrease in the mean temperature of Management (SRM) – where the planet. However, the models point to different impacts in different parts of the interventions are made that seek to world. They also suggest that while Artic sea ice loss would be slower, it would not partially block or reflect sunlight back stop, and the risks associated with higher sea level would continue (Berdhal et al., to space to lower the Earth’s 2014). temperature – and Greenhouse Gas While SRM could theoretically restore global average temperatures to pre- Removal (GGR) interventions, industrial levels, this would alter global hydrology cycles. The precipitation changes including Carbon Dioxide Removal are significant, with major potential impacts on agriculture, water supply, (CDR) technologies. biodiversity and energy production. The highest Stratospheric Aerosol Injection reductions in rainfall and the greatest increased (SAI) is considered the most possibility of droughts are found to be concentrated in tropical and subtropical While SRM could economic and technically practical theoretically restore global form of SRM by its proponents. This areas. There is a strong consensus that average temperatures to pre- involves spreading mineral “dust” 15- average global rainfall would be industrial levels, this would alter 20 km up in the stratosphere to reduced by 4.5 percent. Reductions reduce sunlight and lower are predicted to be greater in global hydrology cycles. The temperatures. “Dust” can be blown monsoonal land regions such as precipitation changes are by pipes (like an artificial volcano) or North America (7 percent) and significant, with major potential by balloons or be distributed by a South America (6 percent) in most impacts on agriculture, water specially-outfitted aircraft. The most studies (Tilmes, et al, 2013; Robock et supply, biodiversity and commonly considered proposal is to al., 2008; Bala and Nag, 2012; energy production. inject sulphate aerosol into the Trenberth and Dai, 2007). stratosphere. This entails a range of Within these regions, heavily populated and impacts and risks, including highly cultivated areas, including Mesoamérica, Central América, the Amazon worsening ozone layer loss, changing Basin and northern South America are expected to have less tropical rainfall, which precipitation patterns and a potential would have significant socioeconomic impacts, particularly on agriculture, water “termination shock” effect, resulting supply and energy production. This makes these areas particularly susceptible to from the sudden change in drastic changes in climate (Marengo et al., 2012). temperature (see below). Blasting sulphates into the stratosphere, enhancing albedo over oceans or land, Net Primary Productivity (NPP) and other SRM techniques will not reduce carbon dioxide concentrations. SRM is an indicator used to show the would merely postpone the impacts for as long as the technology continued to be ability of the terrestrial biosphere to deployed. If the technology was halted, it could result in abrupt and more extreme take up carbon dioxide. It may climate change (Jones A. et al., 2013). provide estimates of the impacts of geoengineering on agriculture (Kravitz et al., 2013). 2 www.etcgroup.org November 2018 Solar Radiation Management: Implications for Latin America Box 2 The IPCC’s Representative Concentration Pathways (RCPs) and geoengineering The Intergovernmental Panel on Climate Change (IPCC) These findings suggest that using CDR would pose uses four different greenhouse gas concentration additional challenges for cooperation between countries. trajectories in its fifth Assessment Report (AR5), known as These limitations, and the lack of technical, economic and Representative Concentration Pathways (RCPs). These are environmental evidence as to the feasibility and viability of identified as RCP2.6, CDR proposals, mean that RCP4.5, RCP6, and RCP8.5, they likely cannot be with each one named after a deployed fast enough to meet possible range of radiative the temperature reduction forcing values in the year levels required. 2100, relative to pre- The UNEP 2016 Emissions industrial values (+2.6, +4.5, Gap Report concluded that +6.0, and +8.5 W/m2, while proposed national respectively). emission reductions plans, These pathways are used in i.e., countries’ Intended climate modeling to describe Nationally Determined four possible climate futures, Contributions (INDCs), all of which are considered would reduce emissions Figure B2.1. Temperature increase (relative to the 1986 possible depending on the – 2005 average) for the RCP scenarios. (IPCC, 2014b) compared to global “business amount of greenhouse gases as usual” emission levels emitted in the coming years. Most (black line in figure B2.2), the scenarios reaching long-term contributions are far from what is concentrations of about 450 ppm of required for an emission pathway carbon dioxide equivalent (CO2 eq) consistent with staying below 2°C in 2100 are considered likely to (blue line). The report estimated keep global average temperature that full implementation of both change below 2°C over the course of unconditional and conditional the century relative to pre-industrial INDCs would imply an emissions levels. Note that only RCP2.6 and gap of 12 gigatonnes of carbon RCP4.5 would supposedly reach dioxide equivalent (GtCO2e) in this goal (Figure B2.1). 2030. This is equivalent to China’s current carbon dioxide emissions The scenarios which keep global from fossil fuel use and industry. average temperature change below This gap reflects the difference 2°C assume the use of large-scale between the INDCs and the least- CDR geoengineering, mainly cost emission level for a pathway to through afforestation and the use of Figure B2.2 Annual Global Total Greenhouse Gas Emissions (GtCO2e) under different stay below 2°C and translates into a bioenergy with carbon capture and scenarios and the emissions gap in 2030 global average increase of storage (BECCS), but they do not (UNEP, 2016). temperature of 2.9 to 3.4°C. assume the use of SRM. Relying on existing CDR technologies would require vast, large-scale This gap has been used by geoengineering proponents and land use changes, and would cause local and regional some

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