Key Findings from the Newest Global Assessment Report on Climate Change

The Environmental and Energy Study Institute (EESI) invites you to watch a briefing on the implications of the Intergovernmental Panel on Climate Change’s (IPCC’s) most recent report—the Sixth Assessment Report—for the upcoming international climate negotiations in Egypt (COP27) and for work on Capitol Hill. The IPCC Assessment Reports are designed to pull together information from around the globe on climate change, including on the physical science; climate impacts and adaptation; and possible greenhouse gas emission trajectories and mitigation opportunities.

Panelists, who participated in drafting sections of the report, discussed key findings from the report and how the information could be used by decision-makers at the national and international levels.

 

Highlights

 

KEY TAKEAWAYS

The Intergovernmental Panel on Climate Change (IPCC) was founded as a scientific body that reviews and assesses the most recent information produced worldwide that is relevant to understanding climate change. The organization now has 195 member countries. Recent changes in the climate are widespread, rapid, and intensifying. They are unprecedented over thousands of years. It is indisputable that human activities are causing climate change. Climate change is already affecting every region on Earth in multiple ways. The changes we experience will increase with further warming. Currently, greenhouse gas emissions will lead to global warming of 3.2 degrees Celsius (5.76 degrees Fahrenheit). To reach the goal of keeping warming below 1.5°C (2.7°F), global carbon dioxide emissions must reach their highest levels before 2025 and must be reduced by 43 percent by 2030. In the same timeframe, methane emissions must be reduced by a third. Climate adaptation saves lives, reduces risks, and has multiple benefits, but it is not equally implemented throughout the world. To accelerate adaptation there needs to be political commitment; strong institutional frameworks; robust and flexible institutions enhancing knowledge; improved monitoring; accountability; and inclusive governance that prioritizes equity and justice. Closing investment gaps will also be necessary to decrease overall emissions. Financial flows are currently three to six times lower than the levels needed by 2030. The Sixth Assessment Report found that human influence on the atmosphere, ocean, and land components of the climate system, taken together, is assumed as unequivocal for the first time in any IPCC assessment report.

 

Dr. Venkatachalam “Ram” Ramaswamy, Director, Geophysical Fluid Dynamics Laboratory, National Oceanic and Atmospheric Administration (NOAA); Working Group I Review Editor, Intergovernmental Panel on Climate Change (IPCC)

• The IPCC was formed by the World Meteorological Organization and the United Nations Environment Programme. It consists of the IPCC Plenary, the IPCC Bureau, and the Executive Committee. The IPCC has three working groups and a Task Force on National Greenhouse Gas Inventories. Each working group has a technical support unit, authors, contributors, and reviewers.
• To generate a report, the IPCC first approves an outline, which is drafted by experts nominated by member governments. From another pool of experts nominated by governments and organizations, the bureau selects authors to frame and write the chapters. Authors prepare a first order draft that undergoes expert review. Responding to those initial comments, the authors then prepare a second order draft that undergoes expert and government review. Authors lastly prepare a final draft that is distributed to the government and authors worldwide. Each IPCC report’s Summary for Policy Makers is reviewed and accepted by country governments and is publish together with the working group reports.
• The Working Group I report is focused on the physical climate science.
• Observations based on global surface temperatures and proxy records from the past 2,000 years reveal that the most warming has occurred in the last 150 years. This rivals the warmest multi-century period in more than 100,000 years.
• The climate system is now out of energy balance. A stable climate would have the same amount of energy going out of the planet compared to the amount coming in as solar energy. Now, there is less energy going out of the system because it is trapped in the atmosphere by greenhouse gases (GHGs). Ninety one percent of this excess energy in the Earth’s system is being absorbed by the ocean.
• Human activities have warmed the climate at a rate that is unprecedented in at least the last 2,000 years.
• Observed warming is driven by emissions from human activities, with greenhouse gas warming partly masked by aerosol cooling.
• Climate change is already affecting every inhabited region across the globe.
• Data shows that GHGs will keep increasing unless there are very tight controls on them while aerosols are predicted to decrease.
• In the IPCC’s SSP5-8.5 model projection, the most unabated scenario in which there are no controls on GHG emissions, global surface temperatures are predicted to increase 5°C (9°F) compared to preindustrial levels.
• With every increment of global warming, changes in regional mean temperature, precipitation, and soil moisture increase. Land is warming faster than the ocean, the Northern Hemisphere is warming faster than the Southern Hemisphere, and polar regions are warming faster than the rest of the globe.
• Human activities affect all major elements of the climate system, but some parts of the system are more sensitive than others, so response times vary from decades to centuries. By 2060, most models predict a practically ice-free summer in the Arctic. This has environmental and economic implications for trans-Arctic navigation and passages through ice, for example.
• Global warming causes sea level rise because warming both expands water and melts land-based ice masses. Though an exact estimate is unavailable, ice sheet instability could cause about one meter (3.28 feet) of sea level rise, which is more sea level rise than is currently modeled in the most unabated GHG emissions scenario.
• Extreme events are projected to be more frequent and intense with every additional increment of global warming. For example, an extreme temperature event that occurred once in 10 years on average in a climate without human influence will likely occur 4.1 times in 10 years.
  • That event will be 1.9°C (3.4°F) hotter if average global surface temperatures increase by 1.5°C. That same event will occur 9.4 times in 10 years and be 5.1°C (9.2°F) hotter if global surface temperatures increase by 4°C.
  • Similarly, a heavy one-day precipitation event that occurred once in 10 years on average in a climate without human influence will likely occur 1.7 times in ten years and will be 14 percent wetter if the planet warms by 2°C.
• Recent changes in the climate are widespread, rapid, and intensifying. They are unprecedented in thousands of years. It is indisputable that human activities are causing climate change. Climate change is already affecting every region on Earth in multiple ways. The changes we experience will increase with further warming.

 

Dr. Debora Ley, Economic Affairs Officer, Energy and Natural Resources, United Nations Economic Commission for Latin America and the Caribbean; Working Group II Lead Author, Intergovernmental Panel on Climate Change

• The Working Group II report covers climate risk, vulnerability, and adaptation.
• As the planet warms, a greater percentage of biodiversity is exposed to dangerous climate conditions.
• Global climate risks include heat stress, water scarcity, food security, and flood risk.
• When multiple extreme events happen close together in time and space, it compounds risks and makes them more difficult to manage. For example, intensifying heat and drought increase heat stress among farm workers. This reduces crop yields and reduces productivity, which then increases food prices and reduces household incomes. These compounding events have local and potentially global effects.
• Worldwide there are between 3.3 and 3.6 billion people living in places that are highly vulnerable to climate change. These places face simultaneous challenges such as limited access to basic services and infrastructure; climate-sensitive income sources; high levels of poverty and unequal income distribution; problems with governance; lack of financing sources; and low levels of trust.
• Even if communities reduce or eliminate climatic risks, there will still be some populations that have increased vulnerability.
• With proactive adaptation, risk decreases. For example, studies find that the risk of heat-related morbidity and of contracting malaria both decrease when proactive adaptation is taken.
• Adaptation saves lives, reduces risks, and has multiple benefits, but it is not equally implemented throughout the world.
• As warming continue to increase, the effectiveness of adaptation might decrease. Adaptation cannot prevent all loss and damage. Warming will disproportionately affect freshwater sources, people living on small islands, and people dependent on glaciers and snowmelt for water. Above 1.5°C, some natural solutions may no longer work. By 2°C, it will be challenging to farm multiple staple crops in many current growing areas, which threatens food security.
• Maladaptation is adaptation that has unintended consequences and exacerbates vulnerability. This includes shifting risk burdens now and over time from one group to another. This can be due to short-term actions, lack of attention to the most vulnerable people, and lack of planning. The most disadvantaged groups are those most affected by maladaptation.
• Working Group II created a systems transitions framework to bring together adaptation and mitigation strategies and analyze their synergies and tradeoffs. The framework has five system transitions: land, ocean, coastal, and freshwater ecosystems; urban, rural, and infrastructure; energy; industry; and society.
• To accelerate adaptation there needs to be political commitment; strong institutional frameworks; robust and flexible institutions enhancing knowledge; improved monitoring; accountability; and inclusive governance that prioritizes equity and justice.
• The report emphasizes climate resilience development, which brings together climate risk reduction, emissions reduction, interdependence with ecosystems, sustainable development goals, biodiversity, and how to shift societal development.
• In Working Group II, this was the first time that Indigenous knowledge was given the same level of consideration as scientific knowledge.
• For many locations on Earth, the capacity for adaptation is already significantly limited. The maintenance and recovery of natural and human systems will depend on the achievement of mitigation targets.
• The magnitude of observed impacts and projected climate risks indicate the scale of decision-making, funding, and investment needed over the next decade if climate-resilient development is to be achieved. Available evidence on projected climate risks indicates that opportunities for adaptation to many climate risks will likely become constrained and have reduced effectiveness should 1.5°C of global warming be exceeded.

 

Dr. Nan Zhou, Senior Scientist, Technical Program Manager - Net Zero World Initiative, Lawrence Berkeley National Laboratory; Working Group III Lead Author, IPCC

• Working Group III focuses on emissions pathways and mitigation opportunities.
• The rate of GHG emission growth is slowing thanks to climate action. There was 1.3 percent growth in emissions between 2010 and 2019 compared to a 2.1 percent increase in earlier decades.
• Renewable energy has seen a sustained decrease in unit costs with a 65 percent decrease in cost for solar energy, 55 percent for wind energy, and 85 percent for electric batteries. In some cases, renewable energy costs are now lower than fossil fuel costs.
• While this has fostered an increase in renewable energy resources, the share of renewable energy capacity in the overall system remains low.
• Currently, GHG emissions will lead to global warming of 3.2°C (5.8°F). To reach the goal of keeping warming below 1.5°C, global carbon dioxide emissions must reach their highest levels before 2025 and must be reduced by 43 percent by 2030. In the same timeframe, methane emissions must be reduced by a third.
• Temperatures will stabilize when we reach net-zero greenhouse gas emissions.
• Every sector currently has options to decrease GHG production to halve emissions by 2030.
• The energy sector accounts for a third of global emissions, and major transitions are required to limit global warming. It is possible to decentralize the energy network rather than having one electricity grid, which would make it easier to transition to renewable energy.
• The report identifies 60 types of individual actions that would decrease global emissions by 40-70 percent by 2050. The most significant action people can take is walking, cycling, and using electric transportation instead of driving gas vehicles. In addition, reducing air travel, making housing more energy efficient, and shifting to a plant-based diet also make a significant difference.
• Electric vehicles offer the greatest impact in the transportation sector, but they must be combined with low- and zero-carbon electricity sources. In addition, alternative fuels like hydrogen and biofuels for aviation and shipping are needed.
• Cities and urban areas must also contribute through better urban planning; sustainable production and consumption of goods and services; electrification; and enhancing carbon uptake and storage through green spaces and trees.
• It is possible for all buildings to reach net-zero emissions by 2050. However, this requires retrofitting existing buildings, investing in mitigation technology in new buildings, and ambitious policymaking.
• Industry, which currently accounts for a quarter of all global carbon emissions, can make materials more efficiently; reuse and recycle; minimize waste; and produce basic materials with low- to zero-emissions. Achieving net-zero emissions in this sector will be challenging.
• Active carbon dioxide removal strategies are also necessary, including biological methods (such as reforestation and soil carbon sequestration) and technological methods.
• Thoughtful land use can promote large-scale emission reductions and store carbon dioxide. This includes protecting and restoring natural ecosystems to remove carbon.
• Closing investment gaps will also be necessary to decrease overall emissions. Financial flows are currently three to six times lower than the levels needed by 2030.

 

Lynn Price, Affiliate (retired Senior Scientist), Energy Technologies Area, Lawrence Berkeley National Laboratory; Working Group III Lead Author (1994-2014), Intergovernmental Panel on Climate Change

• The IPCC was founded as a scientific body that reviews and assesses the most recent information produced worldwide that is relevant to understanding climate change. The organization now has 195 member countries.
• There have been six assessment reports published between 1990 and 2022. The IPCC has also conducted a number of specific reports between each assessment report. During this time, there has been exponential growth in public awareness and peer-reviewed literature on this topic.
• The First Assessment Report (1990) concluded that emissions from human activities substantially increase the atmospheric concentration of GHGs.
• The Second Assessment Report (1995) pointed toward human influence on global climate.
• The Third Assessment Report (2001) found new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.
• The Fourth Assessment Report (2007) said climate change is very likely due to increased anthropogenic GHG concentrations.
• The Fifth Assessment Report (2014 and 2015) concluded that the evidence for human influence has grown since the last assessment, and that it is very likely that human influence has been the dominant cause of the observed warming since the mid-20th century.
• The Sixth Assessment Report (2021 and 2022) brought the most definitive link between human actions and climate change. The authors found that human influence on the atmosphere, ocean, and land components of the climate system, taken together, is assumed as unequivocal for the first time in any IPCC assessment report.
• The Sixth Assessment Report was an incredibly thorough research project, with 782 authors, 199,637 review comments, and 66,000 citations.
• The IPCC will do outreach at COP27 and release a Sixth Assessment Report synthesis on March 20, 2023.

 

Q&A

 

Q: What is it like working with a global team to produce an IPCC report?

Ramaswamy

• It is a very daunting process, and it keeps getting more daunting with every assessment because the amount of research on climate change is exponentially rising. We bring together all that information to write an IPCC report. It goes through lots of reviews, so you cannot be slacking off on it.
• The pandemic forced authors to meet virtually and navigate electronic media platforms, which was challenging, especially when navigating time zones from Australia to Canada.
• Authors were experiencing climate impacts firsthand while writing the report. This fostered a different kind of connection when writing the assessment.

Zhou

• Working in different time zones and across cultures could be difficult.
• People come from many different disciplines. This provides a wide range of perspectives, which form a more well-rounded product.

Ley

• The Sixth Assessment Report was special because it was the first time it was specifically requested by the United Nations Framework Convention on Climate Change (UNFCCC) member states, and it was the first report that brought the three working groups together.
• Natural and social scientists from the three working groups had not worked together before, but I think it brought rich discussions of how to include equity, justice, and ethics considerations into technologies. It also fostered conversation on how social and natural scientists, for example, could better integrate each other’s suggestions.
• This was the first report to mention colonialism as a main cause of vulnerability.

Price

• It must have been incredibly difficult to create the report remotely, as the writing and editing process has historically included discussion and responding to comments in person.

 

Q: What do you see as the main linkages across the three working groups in the report?

Ley

• The topic of extremes has come up between the working groups.
• There was cross-working group collaboration within the feasibility assessment, especially in chapter 18, "Climate Resilient Development Pathways," of the Working Group II report.

Zhou

• Our chapter included adaptation and risk assessment, which had many linkages with others, including alternative fuel, cleaner fuel, and biofuel, many of which come from agriculture. Some of these fuels compete with our food system, so we must consider the link between adaptation and mitigation with impacts on the food system.

Ramaswamy

• The idea of hydrological extremes, namely heavy precipitation or the lack of it, started within Working Group I and cascaded to other groups.
• Hydrological extremes also appeared in the context of warming leading to sea level rise and regional coastal inundation, which then affected tribal communities and various parts of the world.

 

Q: What are one to two of the most important actions we can take to reduce greenhouse gas emissions and adapt to climate impacts?

Ley

• Implementing nature-based solutions to include nature throughout land, energy, and urban systems.
• Justice, equity, and ethics considerations need to be at the center of conversations. It is not just about technology or institutions; it is about people.

Ramaswamy

• On the mitigation side, the assessment points out non-carbon dioxide GHGs, such as methane or black carbon. There are numerous calculations presented where just reducing these GHGs would contribute towards improving Earth's energy balance.
• On the adaptation side, there are clear indications that some regions are going to be more highly sensitive to warming and other extremes than others. Paying more attention to those regions may give them a greater opportunity to protect and preserve assets. There may also be early warning signs in some of these regions of climate tipping points.

Price

• We need more big picture solutions, such as decarbonizing the grid with more renewable energy sources and focusing on storage.
• We also need to increase electrification.

Zhou

• We need systems solutions because approaching each measure mentioned in the report one by one will be very slow. Currently, we are not getting the speed and scale necessary for this transition, so we must think about deploying changes on a systems level.

 

Compiled by Shreya Agrawal and Elina Lingappa and edited for clarity and length. This is not a transcript.

 

This briefing is part of a Congressional briefing series, What Congress Needs to Know About COP27:

Key Findings from the Newest Global Assessment Report on Climate Change

Climate Change Loss and Damage

Natural Climate Solutions

What’s on the Table for the Negotiations?

Climate Summit Recap: Key Outcomes and What Comes Next

To learn about all the briefings in the series, visit eesi.org/cop27.