By Brad Plumer and Eric Niiler , The New York Times.  Excerpt: ...an international team of researchers published a major revision of the emissions scenarios used to study global warming. When scientists try to model how hot Earth could get this century, they typically look at a range of possibilities for how much planet-warming pollution humans might pump into the atmosphere. ...In this latest update, the researchers abandoned a dire — and often criticized — high-emissions scenario known as RCP8.5 that has been prominently cited in thousands of climate studies over the past decade. The authors said the scenario was now “implausible” given recent energy trends. ...The majority of climate scientists still say global warming is a serious problem, and that even more plausible, medium-emissions scenarios can carry grave dangers. But the new paper has raised questions about whether some of the risks of climate change have been poorly communicated or overstated in years past and how bes...

By Paul Voosen , Science.  Excerpt: The  last assessment  of the state of climate science from the United Nations’s Intergovernmental Panel on Climate Change (IPCC), published in its final form 2 years ago, was a monumental effort, with  721 volunteer scientists  synthesizing all available published research. Yesterday, the Department of Energy (DOE)  released  its own climate assessment, as part of a campaign by the U.S. Environmental Protection Agency (EPA) to overturn its landmark endangerment finding from 2009, which found that burning fossil fuels endangers public health and established carbon dioxide as a pollutant EPA could regulate. But the DOE  report —called  A Critical Review of Impacts of Greenhouse Gas Emissions on the U.S. Climate —had fewer authors than IPCC’s: just five. ...Climate researchers say the authors cherry-picked evidence and highlighted uncertainties to achieve the net effect of downplaying the impacts of climate ch...

By Paul Voosen , Science.  Excerpt: The world’s nations convened this week in Hangzhou, China, to plan the next major international assessment of climate science—but without the United States. Late last week, President Donald Trump’s administration denied officials permission to travel to the meeting and cut off a technical support contract for the report, the seventh assessment of the United Nations’s Intergovernmental Panel on Climate Change (IPCC). The decision,  first reported by Axios , is the first time the administration has targeted international climate science. The news caught climate scientists off guard. During the first Trump administration there was no interference with IPCC .... The U.S. has long been a leader of IPCC, which for decades has brought volunteer scientists together, unpaid, to produce influential reports every seven or so years. Katherine Calvin, NASA’s chief scientist, was set to co-lead IPCC’s third working group, focused on climate mitigatio...

https://www.nytimes.com/2023/09/14/climate/sultan-al-jaber-uae-cop28.html By Max Bearak , The New York Times.  Excerpt: The [United Arab] Emirates, made wealthy by decades of oil exports, wants to be seen as a climate-friendly renewable energy superpower, even as it helps lock developing nations around the world into decades more fossil fuel use. Straddling that split is one man: Sultan al-Jaber. He founded the renewable energy company, Masdar, which has invested billions of dollars in zero-emissions energy technologies like wind and solar power across 40 countries. Simultaneously, he directs Adnoc, the national oil company, a behemoth that makes Masdar look minuscule. Adnoc pumps millions of barrels of oil per day and aims to spend $150 billion over the next five years, mostly to ramp up its output. And this year, the United Nations has in effect vested Mr. al-Jaber with one of humanity’s most pressing tasks: steering its annual global climate negotiations [COP 2023; United Natio...

https://www.ipcc.ch/report/ar6/syr/ By Intergovernmental Panel on Climate Change (IPCC).  The  Summary for Policy Makers  (draft) [ https://report.ipcc.ch/ar6syr/pdf/IPCC_AR6_SYR_SPM.pdf ] is marked as "Approved" but "Do Not Cite, Quote or Distribute". That said, there are many many aspects of interest. E.g.:  "A.4.2 Several mitigation options, notably solar energy, wind energy, electrification of urban systems, urban green infrastructure, energy efficiency, demand-side management, improved forest- and crop/grassland management, and reduced food waste and loss, are technically viable, are becoming increasingly cost effective and are generally supported by the public. From 2010– 2019 there have been sustained decreases in the unit costs of solar energy (85%), wind energy (55%), and lithium ion batteries (85%), and large increases in their deployment, e.g., >10x for solar and >100x for electric vehicles (EVs), varying widely across regions. The mix of polic...

https://eos.org/articles/a-climate-mystery-warns-us-to-heed-the-unknown By Jenessa Duncombe , Eos/AGU.  Excerpt: A basic fact about climate change is curiously absent from public consciousness. ... Methane , a potent greenhouse gas, has been rising in the atmosphere at an accelerating rate since 2007. But the cause of the acceleration remains unknown. Today, NOAA  announced  more sobering news. In 2021, methane rose more than other any other year on record, according to a preliminary analysis of weekly measurements taken at 40 sites globally. 2020 also broke records. ...It’s rare to feel like climate change is a mystery anymore. When the Intergovernmental Panel on Climate Change (IPCC) formed, controversy besieged even basic facts: Is the planet warming? Are sea levels rising? Those squabbles have long since ebbed, ...With so much at stake, there’s a heightening sense that the science is settled. Science historian Naomi Oreskes  called  for the end of the IPCC’...

https://www.nytimes.com/2022/04/04/climate/ipcc-report-explained.html By Raymond Zhong , The New York Times.  Excerpt: Current pledges to cut emissions, even if nations follow through on them, won’t stop temperatures from rising to risky new levels.… See also NY Times article, Stopping Climate Change Is Doable, but Time Is Short, U.N. Panel Warns ; and IPCC Synthesis Report .

https://www.nsta.org/blog/15degc-may-not-seem-much-its-really-big-deal-heres-why By Ann Reid, Executive Director, National Center for Science Education.  Excerpt: In 2015, recognizing the existential threat posed by global climate change and the need for coordinated action, nearly 200 nations adopted the  Paris Agreement , a framework for addressing the climate threat on an international scale. A central goal of the agreement was this: Holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change. ...That still might not seem like much, but there are certainly times when a 2.7°F increase would be a cause for concern. For example, if one of my children had a fever of 101.3°F, 2.7°F above normal, it would certainly get my attention.  Fever is just one insta...

https://www.theguardian.com/environment/2022/feb/28/ipcc-issues-bleakest-warning-yet-impacts-climate-breakdown By Fiona Harvey, The Guardian.  Excerpt: Climate breakdown is accelerating rapidly, many of the impacts will be more severe than predicted and there is only a narrow chance left of avoiding its worst ravages, the  Intergovernmental Panel on Climate Change  (IPCC) has said. ...In what some scientists termed “the bleakest warning yet”, the summary report from the global authority on climate science says droughts, floods, heatwaves and other extreme weather are accelerating and wreaking increasing damage. Allowing global temperatures to increase by more than  1.5C above pre-industrial levels , as looks likely on  current trends in greenhouse gas emissions , would result in some “irreversible” impacts. These include the melting of ice caps and glaciers, and a cascading effect whereby wildfires, the die-off of trees, the drying of peatlands and the thawing o...

https://www.sciencemag.org/news/2021/08/climate-change-unequivocal-and-unprecedented-says-new-un-report By  Cathleen O’Grady , Science Magazine.  Excerpt: The report paints an alarming picture but emphasizes there is still time for swift action to mitigate the worst of the projected impacts of climate change. ...Too much focus on targets like 1.5°C can backfire if they are seen as precipices beyond which there is no redemption, Tebaldi says: “People feel this sense of disempowerment.” The reality, she says, is that these targets sit on a continuum where “every little bit of warming counts.” For the first time, the report elaborates on the details of how each increment of warming is expected to play out in regional impacts and extreme events such as flooding, heat waves, droughts, and fire.... See also Eos/AGU article,  What Five Graphs from the U.N. Climate Report Reveal About Our Path to Halting Climate Change   and Climate Change and Extreme Weather Linked in U....

https://eos.org/articles/what-five-graphs-from-the-u-n-climate-report-reveal-about-our-path-to-halting-climate-change By  Jenessa Duncombe , Eos/AGU.  Excerpt: The Intergovernmental Panel on Climate Change’s first assessment report since 2013 describes two illustrative scenarios that keep warming below 2°C—and several others that go wildly offtrack. …The world has warmed 1.1°C compared to preindustrial levels.... Keeping warming below 2°C, and perhaps 1.5°C, is still possible; it’ll take immediate and sustained emissions cuts. ...Net zero carbon dioxide (CO 2 ) [emissions] is a requirement for any long-term climate solution. ...The two scenarios in the report that limit warming below 2°C use carbon removal from the atmosphere during the latter part of the century....

https://newscenter.lbl.gov/2021/08/09/latest-ipcc-report-points-to-urgent-need-to-cut-emissions/ Source: By  Julie Chao , Berkeley Lab News Center.  Excerpt: Our planet’s oceans, forests, and soils perform a valuable service, absorbing half of our carbon dioxide emissions. But the more that our planet warms, the more that these so-called “carbon sinks” weaken in their ability to perform this service. If we continue on our current trajectory of high emissions of greenhouse gases, by the next century not only will oceans and forests absorb less carbon dioxide, they could even reverse their role and become carbon sources. This is one of the key messages from Working Group I of the  Sixth Assessment Report  of the Intergovernmental Panel on Climate Change (IPCC), released today. ...Reports from Working Groups II and III, which focus on adaptation and mitigation, respectively, will be out next spring. ...Another potent short-lived climate forcer is hydrofluorocarbons, or ...

https://eos.org/articles/scientists-and-activists-examine-need-for-climate-action Source:    By Randy Showstack, Eos/AGU. Excerpt: Scientists shouldn’t have to apologize for being advocates “for a fact-based, objective discourse over what is arguably the greatest threat that we face as a civilization.” For Varshini Prakash, the climate crisis “is obviously very depressing” and “terrifying with the timeline that we’re working on” to curb greenhouse gas emissions. However, Prakash isn’t letting that stop her as she works to organize and mobilize youth and others to stop climate change. She is the cofounder of the Sunrise Movement, an organization that advocates for climate action and supports the Green New Deal initiative. She spoke at a 9 December session at AGU’s Fall Meeting 2019 in San Francisco, Calif., on aligning U.S. energy policy with a 1.5°C climate limit above preindustrial levels. The session included climate scientists and activists....

https://eos.org/articles/climate-change-pressures-land-and-food-resources-report-warns Source:   By Randy Showstack, Eos/AGU. Excerpt: Climate change is putting increased pressure on land and food resources while poor land use and food management are also contributing to climate change, according to a new report issued today, 8 August, by the Intergovernmental Panel on Climate Change (IPCC). The special report [ https://www.ipcc.ch/report/srccl/ ] on climate change and land details these impacts and outlines near- and long-term actions that can help to mitigate and stave off far worse impacts. ...Among the impacts that climate change is having on land are increases in the frequency and intensity of weather and climate extremes; threats to food security, human health, and terrestrial ecosystems; contributions to desertification; and effects on land degradation through actions such as increased rainfall intensity, flooding, heat stress, and sea level rise. In addition, the report...

https://www.nytimes.com/2018/10/24/opinion/climate-change-global-warming-trump.html Source:   By Gavin Schmidt, director of the NASA Goddard Institute for Space Studies. Excerpt: The latest report from the world’s climate scientists has made clear the size of the challenge if the world is to stay below the global warming limit hoped for in the Paris climate agreement. Unfortunately, with current trends we are likely to cross this threshold within the next two decades because we are already two-thirds of the way there. But how do we know what is driving these climate trends? It comes down to the same kind of detective work that typifies a crime scene investigation, only here we are dealing with a case that encompasses the whole world. Let me give you my view, which does not necessarily represent the position of NASA or the federal government....   

https://eos.org/articles/ipcc-chair-discusses-limiting-global-warming-to-1-5c Source:   By Randy Showstack, Eos/AGU Excerpt: Several forthcoming reports by the Intergovernmental Panel on Climate Change examine what needs to be done to take control of our climate future. ...With a United Nations climate change conference scheduled for Bonn, Germany, from 6 to 17 November, two high-level reports released this week warn about the increasing risk of climate change. In addition, the Intergovernmental Panel on Climate Change (IPCC) is working on a separate report, to be issued in 2018, about the effects of global warming at 1.5°C above preindustrial levels. A 30 October report from the World Meteorological Organization warned that in 2016, globally averaged concentrations of carbon dioxide surged in 1 year from 400 to 403.3 parts per million, the highest level in 800,000 years. Also, a 31 October report from the United Nations (UN) sounds an alarm about the need for accelerated short...

https://eos.org/articles/ted-cruz-chairs-heated-senate-hearing-on-climate-change Source:   By Randy Showstack, EoS Earth & Space News. For Investigation:   10.3 Excerpt: Republican-invited witnesses reject consensus view of climate change, charge bias in federal funding. Democratic senators decry attempt to stir controversy about well-established climate findings. ...Witnesses Debate the Science. The hearing featured a panel of five witnesses, four of whom were invited by the Republican majority. ...John Christy, professor of atmospheric science and director of the Earth System Science Center at the University of Alabama in Huntsville, ...Judith Curry, chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology in Atlanta, questioned findings of the Intergovernmental Panel on Climate Change, ...William Happer, a physics professor at Princeton University in New Jersey, and Mark Steyn, a journalist and author of books on climate, threats ...

http://www.nytimes.com/2014/11/03/world/europe/global-warming-un-intergovernmental-panel-on-climate-change.html Source:   by Justin Gillis, The New York Times. For Investigation:   10.3 Excerpts: ... The gathering risks of climate change are so profound that they could stall or even reverse generations of progress against poverty and hunger if greenhouse emissions continue at a runaway pace, according to a major new United Nations report. Despite growing efforts in many countries to tackle the problem, the global situation is becoming more acute as developing countries join the West in burning huge amounts of fossil fuels, the Intergovernmental Panel on Climate Change said here on Sunday. Failure to reduce emissions, the group of scientists and other experts found, could threaten society with food shortages, refugee crises, the flooding of major cities and entire island nations, mass extinction of plants and animals, and a climate so drastically altered it migh...