美國環保署:氣候變遷下 需要新治水思維 | 環境資訊中心

美國環保署:氣候變遷下 需要新治水思維

2008年10月08日
摘譯自2008年10月6日ENS美國華府報導,YT Chen 編譯;莫聞審校

艾克(Ike)颶風造成德州淹大水。圖片來源:美國聯邦急難管理局美國環保署2日發布「氣候和水資源策略方案」,其中警告:當氣候變遷影響全美水資源的同時,更強烈的風暴將威脅水利建設,並造成污染逕流流溢的機會升高。此外,海岸線將因海平面上升而內移,海水化學成分的變化也將改變水生動物的棲息地和漁業。

環保署提出的策略資料預測,水溫的上升將可能改變水中污染物的濃度,並且影響水生系統的作用。該資料還提到,新型態的降雨和降雪預計將改變飲水和其他用途的水源供給,並導致水生系統污染程度的改變。

根據策略資料指出,「風暴在熱帶和內陸地區帶來更大的降雨量,提高淹水的危險性、擴大洪泛區、拉大河川流量的差異度(亦即,高流量者流量更大,低流量者流量更小),在高流量時期提高水的速度並加強沖蝕的力道。這些變化將對水質和水生系統有不良影響。例如,暴雨的增加導致了更多的營養物,病原體和毒素被沖刷進流域中。」

因此,該策略建議,水資源管理亟需對起因於氣候變遷的極端天氣提出應變計畫,所需面對的情況包括了風暴、水資源過度使用、以及水資源的缺乏。

環保署水資業務副署長葛倫博斯(Benjamin Grumbles)表示:「水是清淨能源和氣候變遷的關鍵!我們的水資源與氣候對策已劃出因應的實際辦法與時間表,整合治理水、土與能源問題,已達到永續的目標。」

環保署這份策略名為《全國水資源計畫策略︰對氣候變遷的回應》,為主事者提供了淨化水源、飲用水和海洋保護方面的調適步驟,但這不並是法規或條例,並不具法律約束力。

葛倫博斯說,儘管「氣候變遷對水資源影響的確實範圍和時間點,仍存在高度的不確定性」,但這個策略代表著一種自發性的努力,用以評價如何在氣候變遷下,達成我們對於潔淨水資源和安全飲用水目標的最佳化。」

由此策略所勾勒出的想法和回應行動,可說是環保署在中央和各地區水資源管理單位通力合作下的產物。

在布希政府政策轉向之際,該資料也指出,「國際上對地球氣候的長期性科學研究,正形成關於氣候變遷及其對水資源影響的共識。」布希政府於2001年1月任職以來,官員大多否認有關氣候變遷的科學共識的存在。

目前美國環保署仍然未立法規範二氧化碳等溫室氣體;但幾個由美國和墨西哥某些州,以及加拿大部分省份所組成的區域性團體,已著手進行溫室氣體盤查和排放額度交易。

如今,環保署策略資料顯示,「潔淨能源和氣候變遷」將是該單位首要之務,且該署中央和地區辦公室正著手定義在這方面的策略和行動。環保署長史蒂芬‧約翰遜確認。

這項新策略將著重在使國家水資源計畫針對氣候變遷作出回應的44個具體行動。

這些行動隸屬5個主題:緩和、調適、研究、水計畫專業人士在氣候變遷議題方面的教育訓練,以及在國家水資源計畫中氣候變遷相關任務的管理。 例如, 這個策略承認環保署、各州、執行核心水資源計畫的各部落需要繼續達成飲用水,清潔水和隨著氣候變化的濕地保護目標。

溫度日漸提高的空氣和水、天氣型態的轉變,和上升中的海平面,將形成可能需要修改計劃和另行發展新工具的挑戰,以維持過去的發展進程並避免產生危害人體健康和水域生態系統的新危險。

國家水資源計畫將採取下列行動予以回應︰

  • 測量,將影響減至最輕,並以效率適應法管理氣候變遷對水資源的影響,針對我們的標準及允許的計畫進行回應。
  • 根據氣候變遷,積極適應流域保護,濕地和基礎設施計畫。
  • 發展相關工具、標準,和指導方針,並且鑑定最佳實踐理解並且測量化學,生物學,和物理氣候變化對水資源的影響的自然和大小。
  • 使用環境科學、技術和訊息來指導並支援前瞻性的氣候變遷計畫的和管理。

國家水資源計畫將評估新工業部門(包括生質燃料)與現行產業分類下的排放準則,以衡量是否需要在國家污染物排放系統下提出新版或者修訂以技術為主的績效標準。

Stormwater a Major Concern in New EPA Climate-Water Strategy
WASHINGTON, DC, October 6, 2008 (ENS)

More intense storms will threaten water infrastructure and increase polluted stormwater runoff as climate change impacts water resources across the United States, the U.S. Environmental Protection Agency warns in a proposed climate and water strategy issued Thursday.

Shorelines will move as a result of sea level rise, and changes in ocean chemistry will alter aquatic habitat and fisheries, the agency said.

Warming water temperatures are likely change contaminant concentrations in water and alter the uses of aquatic systems, the EPA strategy document projects.

The document adds that new patterns of rainfall and snowfall are expected to alter water supply for drinking and other uses and lead to changes in pollution levels in aquatic systems.

Heavier precipitation in tropical and inland storms will increase the risks of flooding, expand floodplains, increase the variability of streamflows (i.e., higher high flows and lower low flows), increase the velocity of water during high flow periods and increase erosion," according to the strategy document.

"These changes will have adverse effects on water quality and aquatic system health. For example, increases in intense rainfall result in more nutrients, pathogens, and toxins being washed into waterbodies," the document states.

As a result, the strategy advises, water managers will need to expand efforts to plan for and respond to extreme weather events resulting from climate change, including storms, an excess of water, and a lack of water.

"Water is key to clean energy and climate change," said Benjamin Grumbles, EPA's assistant administrator for water. "Our water and climate strategy charts a course for timely and practical action, connecting the dots, drops, and watts for coordinated, sustainable results."

EPA's "National Water Program Strategy: Response to Climate Change" describes steps for managers to adapt their clean water, drinking water, and ocean protection programs, but it is not a rule or regulation and is not legally binding.

While "significant uncertainty about the exact scope and timing of climate change-related impacts on water resources," remains, the strategy represents "an initial effort to evaluate how best to meet our clean water and safe drinking water goals in the context of a changing climate," Grumbles says.

The ideas and response actions outlined by the strategy are the product of a cooperative effort among EPA water program managers in national and regional offices.

In a change of policy for the Bush administration, the document states that, "A long-term, international investment in scientific study of the Earth climate is now resulting in a scientific consensus concerning climate change and its impacts on water resources."

For most of the time since the Bush administration took office in January 2001, officials denied the existence of a scientific consensus on climate change.

The EPA still does not regulate greenhouse gases such as carbon dioxide, although several regional groupings of U.S. states, Mexican states and Canadian provinces have begun to document greenhouse gas emissions and trade emissions permits.

Now the EPA strategy document states, "EPA Administrator Stephen Johnson has identified 'clean energy and climate change' as a top agency priority, and EPA national and Regional offices are working to define strategies and actions in this area."

The new strategy focuses on 44 specific actions for the National Water Program to take in responding to climate change.

They fall within five topic areas - mitigation, adaptation, research, the education of water program professionals on climate change issues and management of climate change work within the National Water Program.

For instance, the strategy acknowledges that the EPA, states, and tribes implementing core water programs will need to continue to meet drinking water, clean water, and wetlands protection goals as the climate changes.

Warmer air and water, changes in weather patterns, and rising sea levels will create challenges that may require modifications to programs and new tools in order to sustain past progress and avoid new risks to human health and aquatic ecosystems.

In response, the National Water Program will:
• measure, minimize and manage the impacts of climate change on water resources using effective adaptation approaches and will be responsive in our standards and permitting programs
• be proactive in adapting watershed protection, wetlands, and infrastructure programs in light of climate change
• develop tools, standards and guidelines, and identify best practices to understand and measure the nature and magnitude of chemical, biological, and physical effects of climate change on water resources
• apply environmental science, technology, and information to guide and support proactive climate change planning and management

The National Water Program will evaluate new industry sectors, including biofuels, and existing effluent guidelines for industrial categories to assess the need for new or revised technology-based performance standards within the National Pollutant Discharge Elimination System.