The fifth US National Climate Assessment offers a few promising notes amid a mountain of grim news about how extreme environmental changes are already here. There's plenty we can do to mitigate the worst of them—but will we?
On November 14, the US Department of Health and Human Services (HHS) released National Climate Assessment 5 (NCA5), a document that offers a few positive signs amid plenty of work still to be done. The landscape for climate change news has been bleak for some time, and this piece plainly highlights that the impact of extreme climate events isn’t going to lessen any time soon. But the document also crafts a trajectory for action based on a few recent successes and projects on the go. It illustrates that the problem can be tackled well, without offering false hope that further improvements will ever be achieved without more commitments from us, to deeper systemic change.
Here’s what’s important to keep in mind, to build on the work so far.
The scale of the problem
Climate change is here, but not equally. While global temperature has risen 2°F (1.1°C) since the late 1800s, the continental US (including Alaska) has warmed 60% faster than the planet as a whole since the 1970s. The temperature during heatwaves can now vary as much as 7°C within the same city, with households in historically redlined (racially discriminated) neighborhoods most likely to be hotter and less climate resilient. Populations with upward of 20% Black citizens will continue to see annual losses from flooding increase at twice the rate of populations with less than 1% Black citizens. Subsistence fishers, Indigenous peoples, rural communities, and coastal populations are already experiencing more frequent yield failures, higher labor risks and costs, and signs of environmental degradation: all impacting local economies, heritage practices, and the broader food network.
Attribution science allows us to better identify the extent to which warming is influencing the severity of extreme weather conditions. The 2021 Pacific Northwest heatwave was 2 to 4°F hotter than it would otherwise have been, and 2017’s Hurricane Harvey had 15 to 20% more rainfall. A billion-dollar disaster now happens, on average, every three weeks in the US. In the 1980s, the inflation-adjusted equivalent happened once every four months. Mortality figures from 2004 to 2018 range from 700 to 1,300 people dying annually from heat-related causes.
More internal displacement is on the horizon, with millions expected to need to leave their homes in California (from fires), Florida (from rising sea levels), and Texas (from flooding). Fires have not only destroyed whole towns but also yielded more frequent and persistent air pollution, diminishing regional quality of life. At the same time, steep reductions in global crop yields, and related climate-induced economic issues, are driving more migrants to the US. But the impact of global scarcity doesn’t stop there; climate-related hits to production elsewhere also spark economic shocks in the US, driving up food and other everyday household costs.
Changing temperatures and habitats are also increasing the range of infectious and vector-borne pathogens, growing the number of invasive species, and disrupting pollination cycles. These factors increase the healthcare burden, reduce ecosystem resilience, and degrade crop production, respectively, in the US.
Compound events are also on the rise. One example, from the West Coast in 2020 and 2021, illustrates the interconnected nature of climate disasters: First, severe droughts, heatwaves, and increased lightning yielded more forest fires, which were exacerbated by strong offshore winds. Droughts also impacted streamflow conditions, changing the land’s ability to handle future run-off and isolating aquatic ecosystems, which fostered algal blooms and saw many species die-offs. After the fires, droughts, and heatwaves, there was less of a natural buffer (via root systems, and well-defined waterways) to hold water from any subsequent storms. Floods and mudslides tore through these regions instead.
Our goal is to keep from reaching global tipping points that will make intervention in such devastating cycles even harder. To keep global warming below 2°C (3.6°F), and ideally below 1.5°C (2.7°F), the world needs to reach net-zero greenhouse gas (GHG) emissions by around 2050. However, it is not on track for this objective, and although the US has made significant strides toward reducing emissions even amid a growing population, these efforts continue to fall short of the need:
While US greenhouse gas emissions are falling, the current rate of decline is not sufficient to meet national and international climate commitments and goals. US net greenhouse gas emissions remain substantial and would have to decline by more than 6% per year on average, reaching net-zero emissions around midcentury, to meet current national mitigation targets and international temperature goals; by comparison, US greenhouse gas emissions decreased by less than 1% per year on average between 2005 and 2019.Chapter 1: Overview, NCA5, HHS, November 14, 2023
For the rest of the decade, climate change impacts are going to intensify. Even if the US can lower emissions faster, it will take years for current GHG levels to subside enough to produce significant easing in global heat and its outcomes. As noted,
When or if warming stops, long-term responses to the temperature changes that have already occurred will continue to drive changes for decades. Put simply, communities across the country are built for a climate that no longer exists.Chapter 2: Climate Trends, NCA5, HHS, November 14, 2023
This situation poses two big problems: how to prevent even worse disasters in the near future, and how to deal with the ones already here. In every region in the US, mitigation projects are underway, and they have been expanding since 2018. But it’s a race against time, and against the complexity of climate change around the globe, to see if these and similar national efforts can achieve their stated goals.
Paths to resilience and change
The basics of mitigating climate change fall into two groups: efforts to reduce GHG emissions in the first place, and efforts to sequester the emissions already here. Reductions come through improved product efficiency, switching to electric, decarbonizing the grid (i.e., not creating electricity with fossil fuels), and better managing energy demands. Carbon uptake can be improved by using landbased ecosystems as carbon sinks, pursuing direct air capture, and engaging in blue carbon projects: building back marine and coastal ecosystems to store carbon, too.
Between 2005 and 2019, the US saw a 12% overall reduction in GHG gases, even with a growing population, due primarily to a shift from coal- to natural-gas-fueled electricity generation. Although this isn’t anywhere close to the 6% annual reduction needed to meet 2050 targets, the change comes with a great deal of knowledge as to what’s needed, and what’s within reach. Improvements to the agriculture sector, for instance, should make the switch to lower-emissions processes and equipment more cost-effective soon. What’s needed now is more consumer choice, general public acceptance, and the completion of a few key technologies: all factors that can be shaped by good policy from government and industry alike.
Sometimes our solutions work at cross-purposes, though. The world’s efforts to reduce other forms of pollutants, such as aerosols, have helped to improve human health and repaired the hole in our ozone layer. However, some aerosols in the atmosphere can defend against global warming, by blocking out more of the sun’s energy. Thus, the more we clean our air for other environmental reasons, the more pressure we’re now under to reduce GHG emissions, to offset the higher amount of solar energy entering our atmosphere to be trapped here.
In the US, the transportation sector is the largest source of GHG emissions, counting for 28.5% of the country’s total in 2021. Current projections don’t yet show GHG emissions and energy use changing sufficiently to meet 2050 targets, but there are some promising signs of transformation in the lower costs of zero- and lower-emissions vehicles, especially in the realm of heavy-duty transport trucks.
The problem that remains is twofold.
First, even as green alternatives are being onboarded faster and at lower costs in this sector, the demand for ground shipping and flights is still growing. While passenger cars presently contribute more to GHG emissions, heavy-duty freight and offroad sources are rising in the ranks due to increased consumption. The International Transport Forum noted that road freight, which constitutes half of all global diesel consumption, is set to double between 2015 and 2050, offsetting any expected efficiency gains and leading to an increase of emissions by that date.
In Chapter 13, the assessment team also noted that, even with the development of advanced engine technologies, the aviation sector could see a 50% increase in fuel use between 2020 and 2050, due to the growing number of flights. Whether this figure will be tempered by runways unable to function at all hours (due to rising heat in many high-risk zones) was not made clear in the document, although writers noted that runways are one of many transport terrains being monitored closely to determine the further impacts of climate change.
(One other complicating factor, implied but not stated, is that as climate change increasingly damages roadways, transport vehicles, and their cargo, it also adds to overall emissions through the cost of replacing roads, trucks, and products.)
The second problem comes from a different environmental pressure created by “going electric”, both through vehicle conversion and with the use of related technologies (e.g., enviromental sensors, building-specific EV batteries, and machine learning and other automation systems). As more vehicles are electrified, greater strain is placed on the electrical grid, which at present is still too reliant on fossil fuels itself. More also needs to be done to ensure that EV batteries are properly recycled, and to reduce the impact of mining key minerals for them.
While the COVID-19 lockdowns gave us excellent data on reducing CO2 emissions, our culture’s return to old routines after the main crisis also illustrated a systemic challenge: We have yet to build a general society that can support a less energy-intensive transport sector. If we ever do, though, we stand to benefit across the board. At present, the workforce struggles with long commutes, diminished health outcomes, and other dangerous working conditions under climate change: all of which yields higher rates of employee turnover, greater losses to institutional memory, and more injuries from inexperience. We could reduce such inefficiencies while changing our approach to transportation for the environment.
Which brings us to the flip-side of “compound events”: because everything is connected, good climate change policy has the ability to improve many other factors of human life, too. In Chapter 18, authors of the NCA5 give the example of tech advances that could allow for cheaper lower-emissions air-conditioning. The introduction of such tech wouldn’t simply reduce emissions; it would also lessen economic disparities exacerbated by current climate change outcomes, by alleviating the impact of heatwaves in lower income neighborhoods.
Other examples include the Ohio Creek Watershed in Norfolk, Virginia, a buffer zone (including flood berm and tidal creek) developed to protect the region from flooding. To ensure that the space wasn’t filled by counterproductive residential, commercial, or industrial builds, the project also entrenched the creation of new civic spaces for other community wellness projects.
In other words, it’s not just possible to address multiple crises at once by tackling climate change holistically: it’s necessary, because many of the consequences of global warming were intersectional from the start.
The political game
The trouble is, we’ve gone a long time talking about climate change in a more compartmentalized way. This leads to us treating climate change as if any investment in our environment is somehow “taking away” from all the rest of our societal concerns. In political debates and on related forums for public discourse, tax policy often gets discussed at a remove from migration pressures, at a remove from environmental crises, at a remove from disease management, at a remove from ideological wars over the fundamental “character” of our state.
But although reports like NCA5 focus on one country, climate change does not honor or abide by human borders. It does not give a hoot about all our pomp and circumstance, or the cultural documents we use to stand apart from neighbors.
Even wars are too often taken for granted as the result of cultural clashes: “they hate our freedom”, “they don’t believe in our gods”, or “they don’t share our values”.
Meanwhile, underpinning many supposedly deeply rooted ethnic conflicts are often much more straightforward attempts to secure territory and resources in times of increased instability and scarcity for the region.
In a chapter on US international interests, NCA5‘s authors reviewed national security issues raised by the climate crisis. The range is vast, and includes not only the struggle for minerals vital to research and development, but also everything from
local instability to geopolitical tension. In addition to the risks of instability and conflict, compounding dynamics include declining agricultural production and food security; recruitment and influence for extremist or violent groups; and declines in state capacity or legitimacy, including potential corruption, where governments cannot effectively respond to extreme weather events or long-term, chronic climate-connected impacts.Chapter 17.2: National Security, NCA5, HHS, November 14, 2023
And yet, it’s all too easy for us to read many of these political factors distinctly. When expressing alarm over the rise of Christian nationalists, for instance, it’s difficult to see the emboldened presence of these figures in today’s politics as an effect of climate change. The US had plenty of fascists in its past, after all, so why shouldn’t we simply focus on the radical rhetoric on its own?
Likewise, why shouldn’t we hash out tax policy solely around notions of whether the rich and corporations are paying their fair share? Or debate social welfare programs and immigration quotas on their standalone merits? Or argue about police funding models as if criminal activity ever exists at a clean remove from every other variable in communal lives?
Compartmentalizing public policy is great for creating single-issue voters on the campaign trail, and for keeping citizens on the defence, forever fighting to retain or carve out social progress one micro-issue at a time.
Seeing the bigger picture, and legislating around it, is much harder. Recognizing that people are fairly tribalist, and will group up whenever they perceive their “tribe” as in danger, doesn’t mean refusing to stand against hateful rhetoric and lousy policy as it emerges. It simply means also seeing what can be done to alleviate the stressors driving tribalists into greater acts of social schism in the first place.
If we want less war, less migration out of misery, and less persecution of ethnic groups over contrived notions of irreconcilable differences, we need to reduce the environmental pressures that foster perceptions of scarcity and in-group thinking in the first place, and thereafter drive up ruinous population collisions.
Easier said than done, of course, as we try to prevent even worse near-future outcomes while weathering climate events that have already driven up internal displacements, global refugeeism, and a wide range of inter-human conflicts. Everyone today has their pet cause, most fueled in large part by anger, fear, and trauma, and yet many of our very different sites of real-world conflict could be effectively addressed by the same overarching commitments.
If we can learn to see the world’s problems in this more comprehensive way.
And if we can grasp the urgency of that task, right now.
Because it stands,
It is not possible to prevent climate change: the current global warming level is already over 1.1°C. The US, across all levels of government, business, and civil society, must both adapt to this reality of a changing climate and prepare for at least some level of additional warming. Inertia in the world’s infrastructure and economic and political systems means that the near-term trend in risk over the next few decades is largely independent of the choice of emissions scenario, and the climate benefits of aggressive action to reduce greenhouse gas emissions are unlikely to be realized in the near term. The faster and more extensive the warming, the greater the risk of climate impacts overtaking the speed of adaptation, as there are both barriers and limits to adaptation. This means the US will need to adapt to a changing climate regardless of future emissions.Chapter 2: Climate Trends, NCA5, HHS, November 14, 2023
And yet, adapting to climate change will require much more than building flood berms and better electric grids to handle new system pressures. As NCA5 makes clear, everything we’re doing on a technical level is nowhere near to close enough.
To get back on track for our 2050 mitigation targets, we need to rise above the tribalist in us all. We need to stop addressing each political issue at a remove from all the rest. We need to remember that all the sound and fury of our current politics, all those ideological and demographic divisions that we think must mean so much, mean absolutely nothing to the natural world changing sharply all around us.
And they won’t mean anything to us, either, for much longer: not if we don’t start putting first the restoration of this planet to which we all—for now—belong.