On Tuesday, it appears, a slim plurality of Americans voted for Hillary Clinton to be president of the United States. However, thanks to the Electoral College sway of Florida and the Rust Belt, the Republican nominee, Donald J. Trump, is now the president-elect of the United States.
The new president will take office at a singular time in the history of our planet. The year 2016 is the first in well over a million in which the concentration of carbon dioxide in our atmosphere did not fall below 400 parts per million. Physics that has been known since the nineteenth century tells us that these high levels of carbon dioxide should make the planet warmer; and, indeed, this year will almost certainly be the warmest on record, with a global average temperature gearing up to be about 2.2°F (1.2°C) warmer than the late nineteenth century average. And, over the past quarter century, global average sea level has risen at a rate of about 1.2 inches per decade – more than twice as fast as the average twentieth century rate. These are all well-established scientific facts.
Yet if the new administration governs as the Republican nominee campaigned, it will not be auspicious for U.S. climate policy. This means the U.S will face a growing set of risks linked to climate change.
Climate policy in the new administration
The president-elect has in the past claimed that climate change is a hoax. He has called for deregulating carbon dioxide emissions, defunding clean energy and climate research, and ripping up the Paris Agreement brokered through the United Nations. He and his supporters in Congress will have the power to do the first two.
The world, however, will forge ahead on reducing emissions without U.S. leadership. The Paris Agreement has already taken effect. While the federal government may not, in the near term, try to to meet the U.S. commitment to reduce its greenhouse gas emissions, states’ policies and market forces can carry the country part of the way.
China, which has a strong public health motivation to meet its commitments, and the E.U., together with India and Japan, are responsible for about half of global emissions. For the next four years, this quartet may have to carry the burden of global leadership needed to realize Paris’s ambitious vision, which calls for bringing net greenhouse gas emissions to zero in the second half of the century to limit additional warming in order to 0.5-1.5°F (1.5-2.0°C above the late nineteenth century average). Meanwhile, China is already bounding ahead to lead the market for clean energy technologies.
There is also a possibility that the president-elect will change course once in office. Even if he does not reverse course on emissions, perhaps he will recognize the need to manage the growing risks created by climate change through adaptation. After all, sea-level rise directly threatens a number of Trump properties, and Trump International Golf Links Ireland has already started planning for it.
Growing climate risks
Contrary to the skepticism the president-elect espoused during the campaign, the climate is changing, and these changes are creating very real risks for ourselves, our children, and our grandchildren. A girl born today can expect to live into the next century. If humanity were to stay on the fossil-fuel-intensive course of the last several decades, the average global temperature would likely rise by an additional 4-8°F (2-4°C) by the end of her life, and the oceans could rise by more than six feet.
These environmental changes will have potentially severe economic consequences that researchers are beginning to be able to quantify. This is one of the reasons that climate change should be at the top of the U.S. policy agenda – and if it is not at the federal level, then state and local governments will need to take up the mantle.
Among the most significant, quantifiable societal impacts of climate change are on human health.
On hot days, people are more likely to die from causes like cardiovascular and respiratory illness. Climate change could reduce cold-related deaths in northern states, but nationally, heat-related deaths will likely swamp this benefit by the middle of the century if we don’t get off a fossil-fuel-intensive path. Climate change will also expand the mosquito and tick season, potentially increasing the risk in the mainland U.S. of now-familiar diseases like Lyme and West Nile, as well as new ones like Zika.
Under any emissions scenario, we will also need to take adaptive measures, such as expanding access to air-conditioned spaces and strengthening communities to ensure that no one in need is isolated. A less lethargic response to emerging disease threats like Zika – funding for which was long delayed in Congress this summer – is also crucial.
Heat and humidity also affect the ability of people to work outdoors. If the sort of temperatures projected for the end of the century under a high-emissions future were to happen today, outdoor workers would most likely lose about 30 working hours per year, reducing the size of the U.S. economy by about US$80 billion.
The Paris Path would cut this number by about a factor of four. Public health and workplace safety measures can also help. And, of course, the increasing replacement of workers by robots could limit the overall economic toll.
Rising seas threaten our country’s coasts. In many coastal areas, streets now flood with above-average high tides, and the higher sea amplifies the flooding caused by storms. If the approximately nine to 13 inches of global average sea-level rise likely by 2050 were inflicted upon today’s economy, average annual losses from coastal storms would increase by about $9 billion. That’s roughly equivalent to a Superstorm Sandy-sized disaster every eight years.
While sea-level rise for the middle of this century is largely locked in, a recent study about the stability of the Antarctic ice sheet suggests that getting on the Paris Path would make a big difference thereafter. If this new study is correct, living up to the Paris Agreement’s vision would reduce the likely global average sea-level rise from three to seven feet by 2100 to a much lower one to two feet.
Either way, we need to increase the resilience of our coastal communities: in some cases through protective measures like raising infrastructure or building sea walls, but in other cases through gradual relocation away from vulnerable areas.
Some of the most worrisome impacts of climate change on the United States may not happen here directly. Extreme heat, extreme rain and extreme drought all measurably increase the risk of civil conflict. And though climate change was probably only a minor contributor to the Syrian civil war, the war’s global consequences has shown how national disasters spill over national borders.
“The impacts of climate change may increase the frequency, scale, and complexity of future missions, including defense support to civil authorities, while at the same time undermining the capacity of our domestic installations to support training activities.”
The president-elect should listen to the generals.
The president-elect’s Electoral College victory was a big surprise, unanticipated by the polls. There are also possible surprises lurking in the climate system, only partially understood by current science and poorly represented in current climate models.
For example, the large-scale circulation of the atmosphere or the ocean could change rapidly, affecting temperatures, rainfall, sea level, and perhaps even how sensitive the climate is to greenhouse gases. Ice sheets could collapse, accelerating sea-level rise significantly faster than we would otherwise expect). Melting permafrost could add carbon dioxide and methane to the atmosphere, amplifying global warming.
Understanding how likely these changes are – and what their consequences for humanity would be – is a critical task for scientific research. If the U.S. government isn’t going to be involved in funding such research, other governments and private philanthropies should be.
Accounting for our nation’s carbon debt
Using fossil fuels is a form of borrowing. It creates benefits for us today, while placing a growing burden of risk on the future. But unlike the national debt, it doesn’t show up on our country’s balance sheet.
Right now, when designing regulations, the U.S. government uses estimates of the ‘social cost of greenhouse gases’ to value climate risks. The central estimate amounts to $42 for a metric ton of carbon dioxide emitted in 2020, increasing over time. This value represents the value in 2020 of all the climate effects of that ton, from the year of its emission through the centuries to come.
These social cost estimates imply that a year of U.S. emissions currently causes about $200 billion of damage. If the U.S. were to maintain its current emissions forever, the present value of all the ensuing damages would amount to about $14 trillion.
If the U.S. were to cut carbon emissions to zero over the next half century, it would reduce this ‘carbon debt’ by about $10 trillion – roughly half the current $20 trillion public debt. This carbon debt should be on the table alongside the public debt in any discussion of our nation’s long-term fiscal health.
Need for strong democracy
Climate change is creating real, large and increasingly measurable risks – but risks can be managed if we face them head on. Critically, our ability to manage these risks depends upon the health of our public institutions.
If the federal government chooses not to face these risks for the next four years, then the responsibility must fall to others. State and local governments do not need federal blessing to reduce greenhouse gas emissions or to prepare to manage climate impacts better. Networks of governmental and nongovernmental organizations could substitute in part for the federal government’s role linking expert knowledge to those affected by climate change. Philanthropic organizations could step up and help fill the gaps created by the lack of federal funding. The world must move forward, with or without the United States.
And all Americans who care about this issue – whether Democrat, Republican, or independent – need to engage, organize, and make their voices heard.