IPCC Working Group III – Mitigation of Climate Change

The 3rd part of the IPCC Fifth Assessment Report deals with mitigating climate change, making it less severe and painful for humans and other denizens of Earth.

The Intergovernmental Panel on Climate Change (IPCC) is an international scientific body sponsored by the United Nations Environment Programme and World Meteorological Organization. Hundreds of scientists and experts periodically review and evaluate the latest information on climate change and prepare a multi-part assessment report to aid global policymakers in understanding climate change, its potential effects, and possible adaptation and mitigation strategies.

IPCC Climate Change 2014: Climate Change Mitigation Report CoverOne can imagine how tricky it must be to create a report that is informative, easily understood, and does not offend anyone. Each word is carefully selected, reviewed, and approved. See below for an example from the Climate Change 2014: Mitigation of Climate Change report.

IPCC finding: “Effective mitigation will not be achieved if individual agents advance their own interests independently.”

My interpretation: If every man acts for himself, game over.

To learn more about the IPCC and the Fifth Assessment Report (AR5) contributions from Working Group I and II read Intergovernmental Panel on Climate Change – Report Central and IPCC Working Group II – Impacts, Adaptation, and Vulnerability.

Degree of Certainty

IPCC reports use degree of certainty levels to qualify and quantify key findings based on type, amount, quality, and consistency of evidence, confidence in the validity of the finding, and the likelihood of some outcome having occurred or occurring in the future.

  • Available evidence: limited, medium, or robust
  • Degree of agreement: low, medium, or high
  • Level of confidence: very low, low, medium, high, or high
  • Likelihood of an outcome or result: virtually certain (99-100%), very likely (90-100%), likely (66-100%), about as likely as not (33-66%), unlikely (0-33%), very unlikely (8-10%), exceptionally unlikely (0-1%)

IPCC AR5 Working Group III Report

On April 13, 2014, the IPCC announced the release of Climate Change 2014: Mitigation of Climate Change by Working Group III. This third installment of AR5 offers strategies and proposals for mitigating climate change between now and the year 2100 with the intent of limiting the increase in global mean temperature to 2° Celsius (3.6° Fahrenheit).

“Mitigation is a human intervention to reduce the sources or enhance the sinks of greenhouse gases”.

Below are some highlights from the 33-page Summary for Policymakers (SPM) that I found particularly interesting, important, or thought provoking.

Greenhouse Gas (GHG) Emission Facts and Trends
  • Anthropogenic (caused by humans) greenhouse gas (GHG) emissions grew on average by 2.2% per year from 2000 to 2010, almost double the yearly rate of 1.3% from 1970 to 2000.
  • Traffic Jam on Los Angeles FreewayCarbon dioxide (CO2) emissions from burning fossil fuels and industrial processes contributed 78% of the total GHG emission increase from 1970 to 2010.
  • In 2010, carbon dioxide accounted for the largest portion of GHG emissions (76%), followed by methane (16%), nitrous oxide (6.2%), and fluorinated gases (2.0%).
  • About half of cumulative anthropogenic CO2 emissions between 1750 and 2010 occurred in the last 40 years.
  • Increased use of coal in relation to other energy sources has reversed a long-standing trend of gradual decarbonization of the world’s energy supply.

Without additional efforts to reduce GHG emissions beyond those in place today, emissions growth is expected to persist driven by growth in global population and economic activities. Baseline scenarios, those without additional mitigation, result in global mean surface temperature increases in 2100 from 3.7 to 4.8°C compared to pre?industrial levels (median values; the range is 2.5°C to 7.8°C when including climate uncertainty). (high confidence)”

Long-term Mitigation Pathways

About 900 mitigation scenarios were reviewed. They covered a wide range of technological and behavioral options associated with various levels of mitigation. Some strategies have co-benefits like reducing pollution, improving food security, or saving money.

Mitigation scenarios in which it is likely that the temperature change caused by anthropogenic GHG emissions can be kept to less than 2°C relative to pre?industrial levels are characterized by atmospheric concentrations in 2100 of about 450 ppm CO2eq (high confidence).”

The low hanging fruit of mitigation solutions would reduce energy use and thus emissions while saving money. Here are a few examples:

  • Accelerating implementation of energy efficiency projects for transportation, buildings, and industry.
  • Changing eating habits, like eating less beef, and eliminating waste in the food chain.
  • Identifying and removing wasted energy and materials from industrial processes.

Mitigation strategies often involve technologies that already exist but may face challenges due to financial obstacles, public resistance, or opposition from industry. Take energy sources for instance.

  • Coal Power Plant with Piles of CoalClosing coal-fired power plants in favor of natural gas power plants would significantly reduce greenhouse gas emissions, but meet resistance from the coal industry and members of the public concerned about natural gas fracking.
  • Renewable energy sources (e.g. solar, wind, and hydro) are available for widespread deployment but need investment money to scale up and face opposition from the fossil fuel industry.
  • Nuclear power is a low-carbon mature energy source, however building new plants is exorbitantly expensive, the process results in radioactive waste, and there is considerable public resistance.

Some mitigation suggestions involve unproven technologies or require substantial governmental intervention.

  • Theoretically, carbon capture and storage could markedly reduce emissions but it is still a relatively untested technology and may not be a viable option.
  • New urban development projects need to be designed and built with climate Green 3D Dollar Signmitigation in mind, yet in many areas where growth is occurring, there is limited access to information and technical expertise, lack of a strong government and regulatory structure, and inadequate financial resources.
  • Economics usually plays a part in government policy decision making which may delay funding of critical mitigation projects because funds are directed elsewhere.

The IPCC report points out that uncertainties and model limitations exist meaning unexpected things may occur. This seems like a huge understatement. The Earth’s climate systems are incredibly complex and no one has a crystal ball.

Yet, uncertainty is not an excuse for inaction. So let’s get to work.

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Author: Linda Poppenheimer

Linda researches and writes about environmental topics to share information and to spark conversation. Her mission is to live more lightly on Earth and to persuade everyone else to do the same.

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