Key Takeaway
We assess that climate change will increasingly exacerbate risks to US national security interests as the physical impacts increase and geopolitical tensions mount about how to respond to the challenge. Global momentum is growing for more ambitious greenhouse gas emissions reductions, but current policies and pledges are insufficient to meet the Paris Agreement goals. Countries are arguing about who should act sooner and competing to control the growing clean energy transition. Intensifying physical effects will exacerbate geopolitical flashpoints, particularly after 2030, and key countries and regions will face increasing risks of instability and need for humanitarian assistance.
• Asabaseline,theICusestheUSFederalScientificcommunity'shighconfidenceinglobalprojectionsof temperature increase and moderate confidence in regional projections of the intensity of extreme weather and other effects during the next two decades. Global temperatures have increased 1.1 ̊C since pre-industrial times and most likely will add 0.4 ̊C to reach 1.5 ̊C around 2030.
• TheIChasmoderateconfidenceinthepaceofdecarbonizationandlowtomoderateconfidenceinhow physical climate impacts will affect US national security interests and the nature of geopolitical conflict, given the complex dimensions of human and state decisionmaking.
Key Judgment 1: Geopolitical tensions are likely to grow as countries increasingly argue about how to accelerate the reductions in net greenhouse gas emissions that will be needed to meet the Paris Agreement goals. Debate will center on who bears more responsibility to act and to pay—and how quickly—and countries will compete to control resources and dominate new technologies needed for the clean energy transition. Most countries will face difficult economic choices and probably will count on technological breakthroughs to rapidly reduce their net emissions later. China and India will play critical roles in determining the trajectory of temperature rise.
Key Judgment 2: The increasing physical effects of climate change are likely to exacerbate cross-border geopolitical flashpoints as states take steps to secure their interests. The reduction in sea ice already is amplifying strategic competition in the Arctic over access to its natural resources. Elsewhere, as temperatures rise and more extreme effects manifest, there is a growing risk of conflict over water and migration, particularly after 2030, and an increasing chance that countries will unilaterally test and deploy large-scale solar geoengineering—creating a new area of disputes.
Key Judgment 3: Scientific forecasts indicate that intensifying physical effects of climate change out to 2040 and beyond will be most acutely felt in developing countries, which we assess are also the least able to adapt to such changes. These physical effects will increase the potential for instability and possibly internal conflict in these countries, in some cases creating additional demands on US diplomatic, economic, humanitarian, and military resources. Despite geographic and financial resource advantages, the United States and partners face costly challenges that will become more difficult to manage without concerted effort to reduce emissions and cap warming.
Scope Note
This National Intelligence Estimate (NIE) is in response to a Presidential tasking to assess the national security impacts of climate change. While climate change effects are forecast to intensify in the latter half of the 21st century and continue well beyond 2100, based on current emissions trends and technologies, this NIE assesses the near- (5–10 years) and medium-term (10–20 years) geopolitical implications abroad—we do not assess impacts to the homeland or DOD facilities. We assume the following during the next 20 years:
• No precipitating world event that would devastate industrial activity will occur that sharply and permanently reduces greenhouse gas emissions.
The scientific content of this NIE, both the observed climate effects to date and the modeled future impacts, were reviewed by the US Federal science agencies on the Climate Security Advisory Council (CSAC). The CSAC is a partnership between the IC and the Federal science community established by Congress to better understand and anticipate the ways climate change affects US national security interests. It includes the Environmental Protection Agency, the Department of Energy, the Department of the Interior/US Geological Survey, the Office of Naval Research, the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administration, and the National Science Foundation.
The IC relies on the broad consensus of scientific studies, modeling, and forecasts from the Intergovernmental Panel on Climate Change, the US National Climate Assessment, and US Federal science agencies as the baseline to assess the geopolitical implications of climate change. We are aware of, but in this estimate do not rely on, the small minority scientific perspectives on climate change ranging from those who consider it nonexistent to those who view it as a near-term existential threat to humanity.
Confidence Levels
The IC uses as a baseline the US Federal scientific community's high confidence in global projections of temperature increase and moderate confidence in regional projections of the intensity of extreme weather and other effects during the next two decades.
The IC has moderate confidence in the pace of decarbonizing the energy sector, given how historically entrenched and slow moving energy systems have been to change and the difficulty of predicting technological breakthroughs. Our confidence decreases after 2030 because government and private sector policies and investments have the potential to drive a more rapid transition.
The IC has low to moderate confidence in assessing how climate change effects could cascade in ways that affect US national security interests as well as the timing and location of potential geopolitical tension, given the complex dimensions of human and state decisionmaking and the challenge of connecting climate, weather, and sociopolitical models.
Discussion
Reports from US Federal science agencies and the Intergovernmental Panel on Climate Change (IPCC) indicate that the burning of fossil fuels has increased the concentration of greenhouse gases in the atmosphere and raised global average surface temperatures about
1.1 degrees Celsius (°C) over pre-industrial levels. Temperature rise has accelerated, and every decade since the 1960s has been hotter than the previous one, according to the National Aeronautics and Space Administration.
International diplomatic efforts since the late 1980s have centered on understanding and mitigating the effects a changing climate poses to human security. The 2015 Paris Agreement for the first time established a global goal of limiting temperature rise to "well below 2 ̊C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 ̊C" by 2100, concluding that this would "significantly reduce the risks and impacts of climate change." US Government and other scientists argue that the risks grow as the temperature rises and could be catastrophic and nonlinear after 2 ̊C if there are tipping points in the Earth's system. (See Annex B.)
• In the Paris Agreement, more than 190 countries agreed to submit updated plans—known as Nationally Determined Contributions (NDC)— every five years that should outline increased commitments to peak and reduce their emissions. NDCs are voluntary and have no enforcement mechanism for non-compliance.
• Developing countries––which have long argued that they should not have to limit emissions because they were late in industrializing, need to use fossil fuels to grow economically, and have historically emitted fewer greenhouse gases––signed on to the Paris Agreement in part because it did not require country-specific emissions reduction targets. In addition, developed countries pledged to mobilize $100 billion a year by 2020 to help developing countries mitigate and adapt to climate change.
Pressure To Decarbonize Will Increase Geopolitical Tensions
Key Judgment 1: Geopolitical tensions are likely to grow as countries increasingly argue about how to accelerate the reductions in net greenhouse gas emissions needed to meet Paris Agreement goals. Debate will center on who bears more responsibility to act and to pay—and how quickly—and countries will compete to control resources and dominate new technologies required for the clean energy transition.
Most countries will face difficult economic choices and probably will count on technological breakthroughs to rapidly reduce their net emissions later. China and India will play critical roles in determining the trajectory of temperature rise.
Policies Not Driving Decarbonization Fast Enough
Given current government policies and trends in technology development, we judge that collectively countries are unlikely to meet the Paris goals because high-emitting countries would have to make rapid progress toward decarbonizing their energy systems by transitioning away from fossil fuels within the next decade, whereas developing countries would need to rely on low-carbon energy sources for their economic development. Quickening the pace and trajectory of the energy transition will depend on reducing key countries' continued dependence on fossil fuels; investing in research, development, and deployment of low-carbon technologies for specific sectors that are hard to decarbonize; and enacting policies to incentivize renewable energy sources.
The current pace of transition to low- or zero-emission clean energy sources is not fast enough to avoid temperatures rising above the Paris goal of 1.5 ̊C. Global energy demand is expected to increase by more than 18 percent by 2040, according to the International Energy Agency's (IEA) modeling of current policies, with fossil fuel use also growing and continuing to account for only a modestly smaller share of supply even though solar, wind, and other clean sources will grow more quickly, particularly after 2030.
• To achieve the 1.5 ̊C goal through shifts in energy, coal use would need to decline, oil use would need to fall immediately rather than plateau in the 2030s, and natural gas consumption would have to peak this decade, according to IEA data and modeling.
• Fossil fuels will be difficult to replace because the large sunk costs of established production systems make them competitively priced, existing distribution networks offer advantages of flexibility and reach, and scaling alternatives to the level necessary to replace them is difficult. Industrial and transportation sectors will struggle to reduce their reliance on fossil fuels because these sectors are the most dependent on the high energy density that fossil fuels provide.
• Solar photovoltaic and wind generation almost certainly will increase worldwide because they are on average the cheapest form of energy to add to an electricity grid in many countries—particularly when factoring in installation and lifetime operating expenses. Accelerating the speed and scale of their deployment would require new manufacturing capacity, changes to electricity grids and markets, and development of more advanced batteries to provide power when there is no sun or wind.
• Nuclearandhydropowerareforecasttomaintain, at most, their current modest shares of energy supply. Some countries are planning to expand nuclear power generation, but others plan to reduce it because of safety concerns and high costs. The development of small modular nuclear reactors may lead to renewed expansion; given long lead times in production, any notable increase in capacity would occur during the latter part of the period of this estimate.
World leaders are increasingly concerned that a window is closing on the opportunity to reduce emissions before irreversible damage to the climate occurs, and many are responding to public and global pressure to act more ambitiously. A growing number of countries are imposing or increasing carbon taxes to discourage emissions and increase the cost competitiveness of clean energy sources and carbon dioxide removal. In addition, private and public investment in these areas is rapidly increasing.
• By summer 2021 more than 90 countries—covering more than 40 percent of global emissions—had submitted updated NDCs. Several had pledged to reach net zero emissions, including Brazil, Chile, the EU, Japan, South Korea, New Zealand, and the United Kingdom by 2050, and China by 2060.
• In March, the European Central Bank announced plans for new capital requirements for banks that have high levels of climate risks on their accounts, and in April, the United Kingdom passed legislation codifying its emissions target. In July, the EU unveiled its emissions reduction roadmap.
• However,fewothercountrieshaveenshrinedthese targets into law or have detailed plans on how to get there. For example, industry analysts estimate a carbon price as high as $100 per ton would be needed to accelerate a shift to clean energy. In addition, we assess that some countries are using a pledge to mask a lack of seriousness.
China and India will play critical roles in determining the trajectory of temperature rise. They are the first- and fourth-largest emitters, respectively, and both are growing their total and per capita emissions, whereas the United States and EU—as the second- and third- largest—are declining. Both China and India are incorporating more renewable and low-carbon energy sources, but several factors will limit their displacement of coal.