Hundreds of scientists are wrapping up a week-long meeting in Stockholm, Sweden where they gathered to discuss and release the first phase of the highly anticipated 5th Assessment Report of the International Panel on Climate Change (IPCC). These Assessment Reports are widely considered to be the most influential scientific studies on climate change. In an effort to shed some light on the significance of this report, we’d like to share some background on the IPCC and some context about this week’s release.
Who is the IPCC and what does it do?
The IPCC (Intergovernmental Panel on Climate Change) is a group of scientists and government delegates from around the world that collaborate to paint a picture of the current state of climate science, the expected impacts, and present best practices on how to respond. The group was formed in 1998 by the United Nations Environment Program (UNEP) and the World Meteorological Organization and is comprised of 195 participating countries, and hundreds of scientists, including some from Southeastern institutions such as Duke University, University of South Carolina, Georgia Tech, University of Miami, University of South Florida, Oak Ridge National Laboratory, the Centers for Disease Control and Prevention (CDC), and the National Oceanic and Atmospheric Administration (NOAA).
The IPCC evaluates a wide range of current, peer-reviewed literature and synthesizes the information into compilations called Assessment Reports. Previous Assessment Reports were released in 1990, 1995, 2001, and 2007. The report scheduled to be released tomorrow is the first of four sections of the IPCC’s 5th Assessment Report (or AR5, for short), divided by subject matter. Each report phase is overseen by a separate working group. Working Group 1 – comprised of 259 scientists from 39 nations – details the physical science of climate change; Working Group 2 reports on the impacts of climate change and how to adapt to them; Working Group 3 writes about how to mitigate climate change; and the fourth phase is a synthesis report that acts as a summary of the three different Working Groups’ information in a more concise format for policymakers. Following Working Group 1’s report expected tomorrow, we will see Working Group 2 release their report in March 2014, Working Group 3 in April 2014, and the synthesis report in October 2014.
What does the report say?
IPCC’s physical science report is unlikely to reveal completely new information: the climate science findings published since the last Assessment Report in 2007 have been widely shared through journals, news articles, social media and national climate assessments. Furthermore, much of the information will be standard ‘Global Warming 101’ material: the earth is warming, the seas are warming and becoming more acidic, sea level is rising, glaciers are melting, etc. A full outline of the contents can be found here.
It has been widely reported (i.e. by the New York Times and BBC) that this week’s report will have a particularly conservative bent; that the report authors will err on the side of conservative projections rather than alarming ones.
A separate New York Times article reports that the low end IPCC sea level rise scenario is just 10 inches by 2100 and the high end scenario is as much as 38 inches by 2100. These numbers vary widely with other projections such as those by NOAA and the National Academy of Science, which have ranges of 8 – 79 inches and 20 – 55 inches by 2100 respectively. Other respected scientists such as Orrin Pilkey at Duke University say that 7 feet rise by 2100 is almost inevitable.
The aforementioned Times and BBC articles also report that since the 2007 Report, the IPCC has revised its estimates on how much temperature rise can be attributed to increases in carbon in the atmosphere. Known as ‘climate sensitivity’, the new IPCC report says that a doubling of carbon dioxide in the atmosphere might cause as little as a 2.7 degrees Farenheit temperature increase, rather than the minimum of 3.6 degrees it stated in 2007. This change could be partly due to slower-than-expected surface temperature increases in recent years or it could be the result of undue pressure from climate skeptics who are loud about the debunked “climate plateau” argument and various other inflammatory anti-science rhetoric.
While the scientists may be more conservative with climate impact projections, they have never been more sure about its causes. The authors state that they are now at least 95 percent confident that global warming is caused by man-made pollution.
What does the report not say?
Similar to previous Assessment Reports, AR5 will likely fail to take into consideration some key longer term contributors to climate impacts in years come, such as the melting of permafrost, which may release a huge amount of carbon, or the acidification of the oceans to the point that they lose effectiveness in seeding clouds in the atmosphere. These effects are feedback loops, which are difficult to project and model, and thus the IPCC does not include them in their analyses. It is probable that there are additional effects to the earth’s climate that are not modeled by the IPCC, whether they be warming, cooling, or neutral effects, which should serve to underscore the importance of proceeding with caution. Policies should reflect some of the uncertainty in climate science and the unmodeled impacts and be prepared for worst-case scenarios. As the adage goes, “better safe than sorry.”
On another note, it is important to read between the lines on some the topics presented within the IPCC reports. While scientific debates exists on when mankind will reach certain benchmarks such as a global temperature increase of 2 degrees Celsius or 3 ft of sea level rise, there little to no debate about if we will reach them. Once we reach them, it’s nearly impossible to think that we could just *poof* stop warming and cease the increasing severity of impacts. In truth, reaching a benchmark such as 2 degrees of warming may just be the beginning. Therefore, even the most conservative projections of climate impacts should be taken seriously and dealt with accordingly.
So what now?
That’s the million-dollar question. IPCC Working Groups 2 and 3 will address climate change adaptation and mitigation in their reports to be released in 2014, but we don’t have to wait for them to come out to know what we need to do. As we’ve known for quite a while, the vast majority of carbon emissions in the U.S. come from power-related activities (power plants, transportation fuel, etc.), so those are the best places to start finding and implementing solutions. Using less energy by increasing energy efficiency should be our first choice and it is the least expensive solution, although it can be difficult to convince some utilities of its merit. Hand in hand with reducing energy consumption is expanding the use of clean, renewable energy that can provide carbon-free power and has proven itself in energy markets worldwide. Reports estimate that the U.S. can supply 80 percent of its power with renewable resources by 2050 while generating wealth and promoting energy equity. Clean fuel technologies such as biofuels and electric vehicles can allow for low- or no-carbon transportation and are breaking ground on innovative energy storage strategies. We need local-, state-, and national-level policies to encourage clean energy development and a groundswell of popular support to stand behind clean energy champions.
The Working Group 1 summary for policy makers on the physical science of climate change will be released on Friday, September 27. The full report will be available on the same page on Monday, September 30.