The United States must move beyond greenhouse gas reductions to develop new strategies to help the public and the economy adapt to the disruptions that will be caused by climate change, a panel of climate experts said at a Capitol Hill briefing co-organized by AAAS.
The panel warned that rising levels of atmospheric carbon dioxide and other greenhouse gases commit the world to rising surface and ocean temperatures, rising sea levels, ocean acidification, retreating glaciers, disruption of biological systems, and weather extremes that will intensify over the 21st century.
By building new homes further inland and renovating existing homes to withstand tidal surges, improving municipal water-efficiency to better cope with droughts, maintaining beaches to resist shore erosion and protect existing coastal communities, and improving weather alert systems, for example, federal and state governments can prepare their citizens and infrastructure for the changing climate, the panel agreed.
Paul Higgins, senior policy fellow at the American Meteorological Society (AMS), said that comprehensive risk-management strategies for the United States must include both mitigation, or reducing emissions, and adaptation, or increasing our capacity to withstand the changing climate.
“Mitigation and adaptation often get mistaken for competing, mutually exclusive alternatives when they are really complimentary approaches with differing strengths and weaknesses,” said Higgins, who served as the event moderator. “Mitigation gets a lot of attention and appropriately so, but we also need strategies to help us deal with unavoidable climate impacts.”
The 8 January briefing at the Cannon House Office Building was the first event in a series developed by the AMS with a new grant from the National Science Foundation’s Paleoclimate Program. The briefing was sponsored by the Water and Power Subcommittee of the U.S. House Committee on Natural Resources and geared for congressional staffers.
The panel featured Michael MacCracken, chief scientist for climate change programs at the non-profit, non-partisan Climate Institute in Washington, D.C.; Kristie L. Ebi, executive director of the Intergovernmental Panel on Climate Change Working Group 2 Technical Support Unit – Impacts, Adaptation, and Vulnerability; Katharine L. Jacobs, a water and climate expert from Arizona who is in the process of being detailed to OSTP to be the assistant director for Climate Assessment and Adaptation; and Susanne Moser, director and principal researcher of Susanne Moser Research & Consulting.
It was organized by the AMS; the American Geophysical Union; the Ecological Society of America; the Pew Center on Global Climate Change; and the AAAS Center for Science, Technology, and Congress.
MacCracken’s presentation focused on approaches lawmakers can take to addressing the key findings of the June 2009 report Global Climate Change Impacts in the United States. The report was prepared by a team of scientific experts from around the country under the sponsorship of the U.S Global Change Research Program.
Speaking on behalf of one of the report’s co-chairs, MacCracken offered a strong case for adaptation, summarizing the impacts of climate change across various regions and social and economic sectors.
He suggested that climate extremes are likely to become more extreme, with wetter regions tending to experience heavier rains and drier regions more intense drought.
Coastal regions will be especially vulnerable, he warned, with impacts including loss of property and inhabitable land due to sea-level rise, storm surges, erosion, and the destruction of vulnerable ecosystems like wetlands and barrier islands.
Further, he added, the United States will experience changes in agricultural growing seasons and the melting of mountain snow pack. And the acidification of the world’s oceans will likely have adverse effects on organisms throughout the food chain, which will affect regions where the economy is closely tied to the seas.
“Global warming and climate change are unequivocally underway . . . and will be a threat to human health and comfort,” MacCracken said. “It’s important that governments at all levels develop strategies to meet these challenges in addition to reducing emissions.”
Ebi called for more federal leadership to encourage state and local governments to explore the effects of climate change on their citizens. For example, she urged policy-makers to conduct studies on which businesses and communities are most vulnerable to sea-level rise, identify the regions most susceptible to floods or drought and effective and efficient options for addressing these risks, and estimate the economic cost of climate change.
An example of an opportunity for facilitating adaptation is to encourage states and regions to explore more sustainable infrastructure. She added that governments may need to build roads further inland where they would be less vulnerable to sea-level rise and weather surges, along with new housing developments that minimize the urban heat island effect, thus increasing resilience during heatwaves.
One of the biggest challenges for adapting to climate change, she said, is “getting individuals, organizations, and institutions to truly understand that the future will be different from the past.”
Ebi added that managing the risks of climate change will be an on-going process. She called on those in and outside government to raise awareness about adaptation, which could increase funding and remove institutional roadblocks and conflicting mandates, among other challenges.”
Jacobs said climate change will have a profound impact on the nation’s water systems, as “the impacts of the changing climate will be largely delivered through the water cycle.”
She explained that temperature is a hydrologic variable —as the temperature changes, so will the demand and supply of water. For example, as the temperature in the American Southwest rises, droughts will occur more often, diminishing the supply, and farmers will increase their demand for the water.
Climate change will also affect the timing of water supply availability as ice pack melting will occur earlier in the year—changing the storage of water during spring and summer months in some watersheds — and a higher percentage of precipitation falling as rain as opposed to snow, which can increase the chance of flooding.
She cited Colorado River studies that estimate a range of potential reductions in runoff from around 10 to 40% by 2050. She pointed out that the critical issue is not precisely how large the reductions will be by what date, but that the anticipated combination of increased demands with reducing supplies require significant attention to adaptation in the near term.
While Jacobs is actively engaged in studies exploring the effects of climate change, she rejects the argument that we don’t know enough to make incremental, important adaptation steps now.
Moser cited California as an example of a state that is proactively exploring both the effects of climate change and potential adaptation strategies. In December 2009, the state released the 2009 California Climate Adaptation Strategy, which is the state’s first, statewide, multi-sector plan detailing how it will address climate change impacts.
She added that California is probably the only state nationwide that regularly allocates substantial funds to study the effects of climate change on their state, thus leaving managers in a better position than many others in understanding climate-related risks.
While 12 states have comprehensive adaptation planning efforts already completed or currently underway, she called for more federal leadership, guidelines, and support encouraging states to prepare for the effects of the changing climate.
“The point of adaptation,” she said, “is to think about the effects of climate change before the house falls into the water, before the tap runs dry.”