The climate challenge

By Stacey Sheppard

As the effects of climate change put our nation’s infrastructure at increasing risk, the need to develop an effective adaptation policy has never been greater.

It is no secret that the Earth's climate is changing rapidly and the impacts of rising global temperatures are proving to have serious, and in many cases, deadly consequences. For years now climate change experts the world over have been warning of these dangers, but it is only recently that they have had the ears of the global population.

Concerns voiced by experts have long been countered with the argument that the Earth's climate has always varied. But as measurements at the Earth's surface show that average temperatures have risen by some 0.4C since the 1970s, scientists are pointing a confident finger at human activity as the main cause of the variation. Rises in green house gases in particular are being held responsible and the fight is now on to reduce our emissions before things spiral irreversibly out of control. It is thought that if green house gas emissions were to continue unabated, the continental United States is expected to warm one-third more than global averages, which, according to the Intergovernmental Panel on Climate Change (IPCC), is predicted to rise 1.1 to 6.4C by 2100.

At the Copenhagen Climate Change Summit held in December of last year, hopes were high that a legally binding global agreement could be reached that would set out strict targets for the reduction of carbon emissions to address the situation. Whilst a legally binding treaty was not concluded at Copenhagen, the so-called Copenhagen accord that emerged does recognize the scientific case for keeping temperature rises to no more than 2C. But in a move that disappointed many of the 192 countries taking part in the summit, the accord does not contain commitments to emissions reductions to achieve that goal. However, politicians are optimistic that a legally binding treaty is foreseeable by December 2010.

Whilst Copenhagen may not have been a total success, what can be said is that at least there appears to be widespread acceptance of the severity of the situation and the need for corrective action. However, evidence suggests that even if we were to cut emissions dramatically as of today, we would continue to see the consequences for years to come as CO₂ can remain in the atmosphere for years. Cutting our emissions may well reduce the threats we face in the future, but in the meantime it is necessary that we focus on adaptation planning at the local, state, and national levels in order to limit the damage caused by climate change, as well as the long-term costs of responding to such disasters.

According to the National Climatic Data Center, the US sustained 90 weather-related disasters between 1980 and 2008 in which overall damages/costs reached or exceeded $1 billion. The total normalized losses for the 90 events exceed $700 billion. The occurrence of adverse weather conditions and natural disasters is increasing in both frequency and severity and we are now confronted with the complex and difficult task of effectively adapting the infrastructure of the United States to deal with the impacts of climate change.

In deep water

In terms of infrastructure, climate change poses an enormous threat to the critical framework of our nation. The main risks include all number of extreme events. As temperatures rise, so too will sea levels ­- the IPCC predicts a rise of 18 to 59cm by 2100 - and this will lead to an increase in coastal flooding and erosion. More than half of the nation's population lives in the 17 percent of its land area bordering the coastlines, and a large portion of the nation's transportation infrastructure is located in coastal plains.

Many roads and rail lines were built along the coast in order to take advantage of level ground or long available rights-of-way. Similarly, many airports are situated in wetlands and other coastal areas that afford large expanses of level ground. Underground transit facilities are also at risk from flooding as many of the ventilation openings and access points are not sufficiently elevated. Low bridges may also be affected by rising sea levels and in the future they may no longer be able to provide the necessary clearance. 

Even if facilities are elevated or protected, the networked nature of the transport system means that they may still be rendered inoperable by sea-level rises. Highways may not be able to function if their approach ramps are underwater and ports may suffer too if their landside facilities - warehouses, container storage areas etc - and access are not adequately protected. 

Come rain or shine

A further consequence of global warming will be changes in annual precipitation, which will not be consistent across the United States. In some areas there will be increased precipitation and therefore flooding, which could render stormwater facilities inadequate, degrade water infrastructure and lead to deteriorating water quality due to run-off and sedimentation. Conversely, in areas where precipitation decreases we will see a drying and shrinking of soil, which will affect the base under pavements and the foundations of many buildings. 

These changes in precipitation levels will also have adverse effects on much of the nation's energy infrastructure. Large quantities of water are used for hydroelectric power production, steam production, and for cooling of power plants. Energy is also used by the water sector for pumping, drinking water, and wastewater treatment. As climate continues to change, and water becomes increasingly scarce in many areas, competition for water will increase. Meanwhile, as the climate continues to warm, demand for electricity will increase, particularly in the Southwest where the US population is increasing fastest. Ninety percent of our nation's electricity is currently generated in coal, natural gas, and nuclear power plants that require large amounts of water for cooling. This will put our energy infrastructure under a great amount of strain.

Rising temperatures will also exert pressure on our infrastructure, both the structures themselves and their operational capabilities. Pavements will suffer from rutting, shoving and potholes whilst rail lines may buckle on very hot days. Airports will also fall victim to temperature rises as many will find that they lack the necessary runway length to take off on hot days when lift is decreased. High altitude airports will suffer most.

Weathering the storm

Storms have been taking their toll since time immemorial, but it is undeniable that recent years have seen an increase in the severity of and destruction caused. From hurricanes and tornadoes to tropical storms, all of these phenomena have the potential to damage and destroy our critical infrastructure.

One of the most serious consequences of these storms can be the implication for emergency management. The increased need to evacuate large portions of the local population from areas at risk from storm damage will inevitably require additional resources.

Storms also pose a threat to our power and energy infrastructure. Onshore pipelines suffer disruptions at the hands of storm-induced power outages. Offshore pipelines, particularly those in shallower waters can also be at risk from the wave action and seabed erosion caused by hurricanes.

Melt down

Climate change will also have a significant impact on freeze-thaw cycles, which will most likely shift in location and duration. Whilst areas that currently suffer damage from freeze-thaw effects will benefit to some extent from the warmer temperatures, there are other areas that will need to invest more in maintenance and repair as temperatures more often cross the freezing point as part of the daily temperature cycle.

Some areas of the US are already experiencing far greater consequences of climate change, in particular the Artic regions, which are warming at an alarming pace in comparison with the rest of the country. These northern latitudes must confront shorter winters, which result in the thawing of permafrost and therefore the destabilisation of the foundations of many infrastructure assets. This is already causing major damage to roads, airports, railways and other critical infrastructure assets.

Adaptation for the nation

It is evident that given the poor condition that the majority of our country's aging infrastructure is already in, action must be taken to protect it. Our infrastructure has enormous value, not only as a capital asset but also as an essential contributor to our economic productivity. The good news is that the true valued has been recognized and infrastructure investment is now a key recipient of funding via the American Recovery and Reinvestment Act of 2009.

Furthermore, some of the funding already accounts for the impact of climate change on infrastructure operation and demand. Much of the investments are focused on renewable technologies and the implementation of a smart grid and $4.5 billion has been allocated to the Army Corps of Engineers for upgrades to flood protection infrastructure.

Although this funding is a step in the right direction, much of it has been allocated in ways that can quickly stimulate spending on shovel-ready projects. However, if investments in infrastructure are to offer more long-term protection against the stresses of climate change there needs to be an adaptation and resiliency strategy that incorporates important changes in policies and practices.

A December 2009 report from bipartisan think tank Resources for the Future, suggests three particular mechanisms and processes to better prepare public infrastructure for the stresses of climate change. Firstly, the adoption a formal asset management approach that could incorporate climate forecasts and enhance our adaptive capacity.

The second suggestion is that we reconsider the location of new and updated infrastructure investments. As the infrastructure, particularly in coastal areas, becomes increasingly at risk from heightened sea-levels and storm surges, investments in these areas must be carefully considered. One thing that needs to be taken into consideration is the fact that adapting to climate stresses is more cost effective during the design phase of a project than as a retrofit.

The third suggestion is that investment in updating design standards should be a longer-term policy goal. A further study that was conducted by Cambridge Systematucs Inc in 2006 concluded that by 2100 temperatures will be approaching those of current design standards and therefore design changes should be made now to enable facilities to cope with the higher temperatures of the future.

The study also concludes that highways in some regions should be redesigned in order to accommodate the predicted sea-level changes as part of a comprehensive urban redesign strategy. Likewise, efforts to identify and protect bridges at risk from intense storms should be a major priority, particularly as bridges have much longer lifecycles than a lot of other infrastructure assets.

It is therefore important that the planning and design stages take into account the predicted effects of climate change and not just historical data. Investment in new infrastructure assets and the maintenance of existing assets need to focus on the changing climate we face in the future. Only by incorporating adjustments in infrastructure planning, design, construction, operation and maintenance can we significantly enhance our adaptive capability.

CASE STUDY: The impact of climate change in Alaska

Over the past 50 years, Alaska has warmed at more than twice the rate of the rest of the United States. In fact, no place on Earth is warming faster. As a result, the impacts of climate change are much more pronounced in Alaska. Due to the influence that the Earth's polar region has on the climate and oceans across the globe, Alaska's plight has gained widespread interest from the US and world leaders.

Global warming is causing a number of worrying changes to take place in Alaska. Over the past 30 years, there has been a sharp reduction in the extent and duration of snow-cover, shorter river- and lake-ice seasons, melting of mountain glaciers, sea-ice retreat and thinning, permafrost retreat, and increased depth of summer thaw. The main consequences of these changes are increased coastal erosion, landslides, and sinking of the ground surface, and consequent disruption and damage to forests, buildings, infrastructure, and coastal communities.

Permafrost underlies most of Alaska and projections state that thawing will accelerate with a predicted 10 to 30 feet of permafrost thawing by 2100. Recent studies have also estimated that over the past few decades there has been an arctic-wide reduction in annual average sea-ice extent of about five to10 percent and a reduction in average thickness of about 10 to15 percent.

The retreat of sea ice has dangerous consequences as it allows larger storm surges to develop, increasing the risk of inundation and increasing erosion on coasts already made vulnerable by permafrost thawing. At 33,000 miles, Alaska has more coastline than the other 49 states put together. Increases in the frequency and intensity of storm surges and the resulting coastal erosion puts many coastal villages at extreme risk. The General Accountability Office (GAO) estimates that 86 percent of native Alaskan villages are threatened by erosion and flooding. Many of these coastal towns are now facing the prospect of relocation at great expense.

A study by the National Commission on Energy Policy, estimates that the cost of maintaining Alaska's public infrastructure will rise by 10 to 20 percent by 2030, costing the state an additional $4 to $6 billion. However, the report also states that by 2030, strategic adaptation could reduce the costs imposed by warming from 0 to 13 percent, depending on the extent of warming. Strategic adaptation is therefore of paramount importance in Alaska.

CASE STUDY: The impact of climate change on California's energy infrastructure

California is also experiencing climate change impacts, including sea level rise, increasing temperatures, shifting precipitation trends, extreme weather conditions, increasing size and duration of wild fires, and earlier melting of the Sierra Nevada snowpack. All of these impacts have a great effect on the energy infrastructure of California, including supply, demand, conversion, delivery and use of energy.

During the past century the sea-level along the coast of California has risen by about seven inches. Sea level rises are predicted to accelerate at significantly higher rates than previously expected. Recent estimates indicate that by 2050 sea level rise could range from 11 to 18 inches higher than 2000 and by 2100 levels could be 23 to 55 inches higher than 2000. According to the US Geological Survey's Coastal Vulnerability Index, many of California's open coastal areas are rated as having 'high' or 'very high' vulnerability to sea level rise.

Many of California's power plants are at risk from climate change either through sea level rise, which could flood low-lying facilities, or through increased storm frequency or intensity, which could affect offshore water intake and discharge pipes. Rising ambient temperatures could also decrease the efficiency of conventional, fossil-fuel burning power plants as well as the efficiency of transmission and distribution lines. Although transmission lines in California are designed to withstand high temperatures, the forecast increase of wild fires in the region could affect the import and transmission of electricity from remote areas - California imports 30 to 35 percent of its electricity from remote regions and current energy policies are expected to increase these levels. Increases in remote generation coupled with increased likelihood of wildfires could create significant vulnerability in California's transmission infrastructure. 

Hydro-electric plants will also suffer as a warming climate could result in a 19 percent reduction in power generation. The generation of renewable energy will also be affected by climate change depending on the availability of water, biomass, solar radiation and the intensity of wind patterns.

As temperatures rise in California, energy demand will also increase as people rely more often on air conditioning. This will put increasing pressure on energy infrastructure and could lead to power outages.