New National Climate Assessment Shows Climate Change Is a Threat to Our Economy, Infrastructure, and Health

The Fourth National Climate Assessment, Volume II, was released today. The much-anticipated report, prepared by a consortium of 13 US federal government agencies, makes clear that climate change is already here--as evident from the worsening flooding, wildfire seasons, droughts, and heatwaves the nation has been experiencing. What's more, the report highlights that as climate change worsens, risks to our economy, infrastructure, health and well-being, and ecosystems will grow significantly. Urgent action is needed to lower heat-trapping emissions and invest in making our economy and our communities more prepared to withstand climate impacts.

Climate change is already imposing economic costs

The NCA reiterates that human-caused emissions of heat-trapping gases are the dominant cause of observed global warming over the last century; there is no other credible explanation for it. Observations show that annual average temperatures across the contiguous US have risen by 1.8degF since the beginning of the 20^th century.

The NCA explains that as temperatures rise, the latest science and data point to a range of worsening impacts. For example, as oceans have warmed and expanded and as land-based ice has shrunk due to warming temperatures, the annual medial sea level along US coasts (with land motion removed) has increased about 9 inches since the early 20^th century. Warmer, drier conditions have contributed to an increase in wildfire activity in the western US and Alaska over the past several decades.

The new report also starkly highlights the billions of dollars of economic losses that are already occurring from climate-related events. Just a few startling examples:

• Flooding along the Mississippi and Missouri rivers in 2011, triggered by heavy rainfall, caused an estimated $5.7 billion (in 2018 dollars) in damages.
• Drought in 2012 caused widespread agricultural losses to crops and livestock, and low water levels along the Mississippi affected transportation of goods along the river, resulting in an estimated $33 billion (in 2018 dollars) in damages nationwide.
• The costs of rebuilding Puerto Rico's electricity infrastructure, which was badly damaged by hurricanes Irma and Maria, have been estimated to be $17 billion (in 2017 dollars).
• Annual federal fire fighting costs have ranged from $809 million to $2.1 billion per year between 2000 and 2016.
• In 2012 and 2013, massive wildfires followed by floods in the Fort Collins, CO area washed out transportation infrastructure and caused $2 billion (in 2013 dollars) in total damages.
• In 2012, sea surface temperatures in the Northeast continental shelf rose about 3.6F above the 1982-2011 average (an extreme manifestation of a warming trend observed in the area), triggering a glut of lobster and causing a severe price collapse.
• The city of Charleston has estimated that each high-tide flooding event that affects the cross-town costs $12.4 million and over the past 50 years the resultants gross damages and lost wages have totaled over $1.53 billion.
• Climate changes--including sea level rise, diminishing snowpack, wildfires and drought--are significantly affecting the traditional subsistence activities, livelihoods and sacred cultural resources of indigenous peoples. In some cases, they are even being forced to consider relocation.

There are also many examples of costs that are hard to quantify in just dollar terms but are surely significant, including harms to human health (both physical and mental), ecosystems and assets of cultural value.

Costs will mount with unchecked climate change

Across the nation, many economic sectors--including agriculture, forestry, fisheries and tourism--are at risk from a warming climate. Much of our nation's infrastructure--roads, bridges, ports, airports, water and waste water systems, electricity infrastructure, dams--which underpins our economy and way of life is also greatly exposed. Even without climate change, aging infrastructure and decades of under-investment already pose significant challenges; climate change will magnify them.

As the report says, the assumption that current and future climate conditions will resemble the recent past is no longer valid. We'll need to prepare for a climate-altered future.

As climate change worsens, some major challenges to our society and economy will likely include:

• Decreases and variability in water availability in some parts of the country, including the Southwest.
• Increases in extreme precipitation in some parts of the country (such as the Midwest and Great Plains), causing flooding and infrastructure damage
• Accelerating sea level rise, putting at risk homes, infrastructure and other valuable assets in the coastal floodplain.
• By the middle of the century, the annual area burned in the US could increase 2-6 times from the present, depending on the geographic area, ecosystem and local climate, with the western US and Alaska at particular risk.
• Coral reefs in the US Caribbean, Hawaii, Florida and the US Pacific islands are already affected by bleaching and disease. The loss of recreational benefits alone from coral reefs in the US could reach $140 billion by 2100.
• According to one study, $1 trillion in national wealth held in coastal real estate is at risk of rising seas. (A recent UCS study also found that high-tide flooding could put over 300,000 coastal homes and commercial properties in the lower 48 states with a collective market value of about $136 billion in today's dollars at risk within the next 30 years. By the end of the century, over 2.5 million homes and commercial properties currently worth more than $1 trillion altogether could be at risk).
• Worsening health impacts including increased mortality and morbidity from worsening heatwaves and ozone pollution and pollution from wildfires. Risks of allergic illnesses and vector-borne diseases (i.e. borne by vectors like ticks and mosquitoes) such as Lyme disease could also worsen in some parts of the country.
• Inland flooding is anticipated to result in average annual damages to bridges of $1.2 to $1.4 billion each year by 2050. Nationally, the total annual damages from temperature and precipitation to paved roads could be as high at $20 billion in 2090 under a high emissions scenario.
• Growing risks of compound extreme events--where more than one hazard occurs at the same time in the same place-- and cascading infrastructure failures which can multiply risks to people, the environment and the economy.
• Pressures on the energy system, including increased demand for electricity as heatwaves worsen, power failures caused by storms and flooding, system failures and inefficiencies caused by extreme heat, and reduced availability of water for hydroelectric systems.
• Disproportionate risks to low-income communities, tribal communities and communities of color who may be more exposed to climate impacts and may have fewer resources to cope with them.

Our Emissions Choices Matter (Greatly!)

The NCA also includes information about the costs of climate change under different emissions scenarios, making clear that limiting emissions can make a huge difference in climate-related damages and costs. Many of these estimates come from a ground-breaking underlying study by the EPA released last year.

For example, health-related impacts and costs could be 50 percent lower under a low emissions scenario (RCP4.5) v. a high-emissions scenario (RCP8.5). Damages to roads and electricity infrastructure can be reduced by about 60 percent. Under RCP8.5, almost 1.9 billion labor hours across the national workforce are projected to be lost annually by 2090 due to the effects of extreme temperature on suitable working conditions, totaling over $160 billion in lost wages per year; Under RCP4.5, about 50 percent of this could be avoided. (These estimates generally do not include assumptions about adaptation).

A clarion call for action

Following on the heels of the IPCC 1.5degC report, the NCA is yet another clarion call to action. Although the report itself is not policy-prescriptive, its findings are directly relevant to policymakers and planners from the local and state to the national level. Given the significant economic implications, the private sector also has a strong stake in addressing climate change and driving innovative solutions.

It's pretty clear that we should do everything we can to limit climate change and avoid some of the more extreme impacts and costs.

That means limiting heat-trapping emissions across the economy. The energy sector must get more efficient and switch to low-carbon sources of energy wherever possible. We'll need to electrify as many energy end-uses as possible, while switching to low-carbon electricity. We'll need to invest in the infrastructure to make all this possible, including ramping up low-carbon power sources, transmission and energy storage. And we'll need to invest in research, development and deployment of new low-carbon technologies and technologies to capture and permanently sequester carbon.

The good news, as the NCA points out, is that parts of the energy sector are already undergoing a low-carbon transition--we just need to accelerate and broaden it. For example, US power sector emissions have fallen 28 percent from 2005 levels, as the nation has transitioned away from coal to natural gas and renewable energy. The falling costs of renewable energy are already making wind, solar and other forms of low-carbon electricity an attractive choice in many states, including Texas, Iowa, Kansas and California. The Pueblo of Jemez has installed the first utility-scale solar facility on tribal grounds, and tribes and Alaska native communities around the country are pursuing energy efficiency and clean energy-related projects.

We'll also have to invest in keeping our nations forests and lands healthy so that they can continue to draw carbon dioxide out of the air and store it. We will likely also need to invest in other so-called 'negative emissions' technologies.

And alongside these ambitious efforts to cut carbon emissions, we'll have to invest in preparing for the climate impacts we have already locked in and that are likely to get worse. Incorporating the knowledge, insights and choices of frontline communities will be critical to the success of these efforts.

It's time to put pressure on Congress and the administration

Releasing the NCA the day after Thanksgiving is a transparently underhanded and shameful ploy by the administration to try to bury the science. But there's no way to ignore the damaging and costly climate impacts our nation is already experiencing. Even as the need for urgent action is evident, we have an administration that is trying at every turn to stop or reverse climate and clean energy policies, and sideline the science.

The NCA points out that our global emissions choices today can determine whether we can limit temperature increase to 3.6degF (2degC) or less in line with the Paris Agreement goals--or whether we end up with runaway temperature increases of 9degF (5degC) or more.

The biggest challenge to ambitious climate action remains political will. As a new Congress is convened in Washington, and new legislatures and governors take office around the country, we need to put pressure on our policymakers to act in our best interests in light of the latest science.

There's no time to dither as climate impacts and costs mount around the nation. We can't continue to wallow in ideological fights about whether or not people "believe" in climate change. Let's implement commonsense, ambitious measures that deliver climate benefits, while protecting our economy and well-being.

A comprehensive infrastructure bill that delivers low-carbon energy, climate resilience, jobs and public health benefits would be a great start.