Patricia Malo de Molina.
Chief Communication Officer of Abengoa.
The third U.S. National Climate Assessment (NCA) was recently published. This document was put together by a team of more than 300 experts who were in turn guided by 60 members of the National Climate Assessment and Development Advisory Committee, forming the largest and most diverse team ever assembled to produce an assessment of the climate of the U.S.
The data contained in this report are, to say the very least, revealing. Revealing because they once again highlight the importance of several issues about which U.S. citizens are already aware, and revealing because they attribute all these phenomena to the activities of the country’s inhabitants. The report discusses the effects of climate change by geographic region in the United States and by economic and social sectors (agriculture, energy and health). In addition, as this document confirms, climate change stands as one of the biggest threats to human health and wellbeing: more extreme weather events, forest fires, poorer air quality and the spread of diseases carried by insects, food and water.
The NCA report predicts that climate change caused by human activity will continue and accelerate significantly if global greenhouse gas emissions continue to rise as they have done up to now. Climate change-related impacts are already very much in evidence across many sectors and are expected to have an increasingly disturbing effect in the 21st century.
The advisory committee, formed by staff from several universities (Florida, Louisiana, Alaska, Michigan and Washington), research institutes (Hawaii Institute of Marine Biology, Georgia Institute of Technology), NGOs (The Nature Conservancy) and companies (ConocoPhillips, WestLand Resources, Inc., Monsanto Company), base this document on a large volume of peer-reviewed scientific research, technical reports, as well as other publicly-available sources, scientific reports and publications, and information from the IPCC.
The report, which was reviewed by experts from the National Academy of Sciences, the 13 federal agencies in the U.S. Global Change Research Program and the Federal Committee on Environment, Natural Resources and Sustainability, is essentially divided into two parts: climate trends and the regional effects of climate change. With regard to climate trends, the NCA conducted an analysis of changes in weather patterns since the mid-20th century, as well as its effects on the population, the economy, natural resources and infrastructure. In the same way, it analyses the effects of climate change at a regional level with the distribution shown in the map below (drawn from the report).
This exhaustive analysis leads to the essential conclusion already mentioned above that the global warming of the past 50 years is due in large part to human activities. Indeed, average temperatures in the U.S. have increased 1.3 °F to 1.9 °F since 1895; and the majority of this increase has taken place since 1970.
In the same way, some extreme weather phenomena have increased in recent decades and the evidence is new and stronger. In the past 50 years, a large part of the United States has experienced an increase in prolonged periods of excessively high temperatures, torrential rain and, in some regions, the most severe droughts in recent years. Indeed, the ability of ecosystems to absorb the impacts of extreme events such as fires, floods and severe storms is being diminished by the effects of climate change.
In relation to water resources, the NCA highlights that the infrastructure is being damaged by rising sea levels, torrential rain and extreme heat; damage that will be exacerbated in the future over the short- and medium-term. The oceans are becoming warmer and more acidic, which affects ocean currents, their chemical properties and marine life. While water quality and the reliability of the water supply are being put at risk, affecting all ecosystems in a multitude of ways and also impacting on human activity, for instance agriculture, which is so heavily affected by changes in the climate.
Planning to adapt and mitigate climate change is more and more widespread and present in our activities; nevertheless, the efforts made thus far have proved insufficient in avoiding the social, environmental and economic consequences, which are increasingly negative.
Regional effects of Climate Change (as shown in a table from the document):
Ultimately, this document highlights California’s Global Warming Solutions Act as a positive measure. This Act aims to set a limit on greenhouse gas emissions and reduce them back to 1990 levels by 2020. The state program caps emissions using a system based on carbon credit trading and limits electricity generation from coal and oil.
The NCA report concludes by proposing some initiatives that could help to mitigate the effects and alleviate the damage caused by climate change. In this regard, it proposes focusing efforts on improved management of torrential rain, adaptation and mitigation in cities, the implementation of emissions cap-and-trade projects, such as the one developed in the north-eastern states; promoting renewable energy (wind, solar and geothermal) in the southeast and consolidation of the transformation of the electricity generation system undertaken by five of the six states in the southeast.