climate change

A Few Takeaways from the “State of the Climate in 2022”

Map of significant global weather and climate anomalies and events of 2022.

Record-high greenhouse gases, sea levels, monsoons, and droughts—and a volcanic vapor injection

By Michael Alexander, Lead, Atmosphere Ocean Processes and Predictability (AOPP) Division, NOAA, and BAMS Special Editor for Climate

The annual NOAA/AMS State of the Climate report has just been released, with a comprehensive global look at the climate in 2022. Produced by the NOAA National Centers for Environmental Information (NCEI) and the American Meteorological Society, the State of the Climate Report maps out the complex, interconnected climate phenomena affecting all parts of the globe. It also charts global progress in observing and understanding our climate system. 570 scientists from 60 countries contributed to this year’s report, including a rigorous peer review, making it a truly global endeavor. 

As the senior editor on this project, I wanted to share with you a few highlights. Click here to read the full report, published as a supplement to the Bulletin of the American Meteorological Society.

New record-highs for atmospheric greenhouse gases CO2, methane, and nitrous oxide.

It was yet another record-setting year for atmospheric carbon dioxide and other greenhouse gases. 2022 saw an average concentration of 417.1 ± 0.1 ppm for atmospheric CO2; methane and nitrous oxide also reached record highs. 

Graphs of yearly global surface temperature compared to the 1991-2020 average for each year from 1900 to 2022, from 6 data records, overlaid on a GOES-16 satellite image from September 22, 2022.  Image credit: NOAA Climate.gov.

Warmest La Niña year on record.

Despite being in the typically cooler La Niña phase of ENSO, 2022 was among the six warmest years on record, and was the warmest La Niña year ever recorded. Summer heat waves left annual temperatures at near-record highs in Europe, China, the Arctic, and Antarctica (parts of Europe set daily or seasonal heat records), and New Zealand experienced its warmest year ever. High-pressure “heat domes” helped elevate local temperatures in many areas, including parts of North America and Europe. 

Record-high global mean sea level and ocean heat.

Global mean sea level reached 101.2mm above 1993 levels, setting a new record for the 11th year in a row. 2022 also saw record-high global ocean heat content (as measured to 2000 meters below the surface), although La Niña moderated sea-surface temperatures.

Image credit: NOAA

Complex climate picture.

Global warming trends continued apace, but of course numerous large-scale climate patterns complicated the picture. In 2022 we saw the first “triple-dip” La Niña event (third consecutive La Niña year) of the 21st century. The Indian Ocean Dipole had one of its strongest negative events since 1982, which led to increased temperatures and precipitation in the eastern Indian Ocean. Along with La Niña, this contributed to record-breaking monsoon rains in Pakistan that caused massive flooding and one of the world’s costliest natural disasters. We also had a positive-phase winter and summer North Atlantic Oscillation affecting weather in parts of the Northern Hemisphere. 

A bad year for drought.

For the first time ever, in August 2022, 6.2% of the global land surface experienced extreme drought in the same month, and 29% of global land experienced at least moderate drought. Record-breaking droughts continued in equatorial East Africa and central Chile. Meanwhile, parts of Europe experienced one of their worst droughts in history, and China’s Yangtze River reached record-low levels.

Warmth and high precipitation at the poles.

2022 was the firth-warmest year recorded for the Arctic, and precipitation was at its third-highest level since 1950. The trend toward loss of multi-year sea ice continued. Meanwhile, Antarctic weather stations recorded their second-warmest year ever, including a heatwave event that collapsed the Conger Ice Shelf, and two new all-time record lows in sea-ice extent and area set in February. On the other hand, record snow/icefall due to atmospheric rivers led to the continent’s highest recorded snow/ice accumulation since 1993.

Image credit: NOAA

Notable storms: Ian and Fiona.

85 named tropical cyclones were observed across all ocean basins, an approximately average number. Although there were only three Category 5 storms, and the lowest recorded global accumulated cyclone energy, the year produced Hurricane Ian, the third-costliest disaster in U.S. history, as well as Hurricane Fiona, Atlantic Canada’s most destructive cyclone.

Massive volcanic injection of atmospheric water vapor.

The Hunga Tonga-Hunga Ha’apai submarine volcano in the South Pacific injected a water plume into the atmosphere of unprecedented magnitude (146+/-5 Terragrams, about 10% of the stratosphere’s total water) and height (reaching into the mesosphere). We don’t yet know what, if any, long-term effects this will have on the global climate, although the increase in water vapor has interfered with some earth system observations. 

The full report is a comprehensive and fascinating analysis of our climate system in the previous calendar year. I urge you to read it and communicate your own takeaways from the State of the Climate in 2022. You can read the press release here.

Infographic at top: World map showing locations of significant climate anomalies and events in 2022. Credit: NOAA.

An Anticipated Increase in Earth's Strongest Storms

GoniA little more than two weeks ago, Supertyphoon Goni blasted ashore in the Philippines with top sustained winds of 195 mph, becoming the strongest landfalling tropical cyclone on record. It topped STY Haiyan’s 190 mph land strike just seven years ago. With Hurricane Iota in the Caribbean explosively intensifying 100 mph in under 24 hours to reach Category 5 intensity Monday, it set a new record of five consecutive years of Cat 5 hurricanes in the North Atlantic tropical cyclone basin. Among the seven catastrophic hurricanes, starting with Matthew in 2016, were Dorian and Irma, packing 185 mph and 180 mph steady winds, respectively, with peak gusts well over 200 mph.
Goni is the latest formidable example of an increasing trend in tropical cyclone intensity. While Goni established a new landfall wind intensity record, Iota and other recent major hurricanes Eta, Zeta, and Delta set or challenged records for most intense hurricanes so late in the season.
PercentilesJames Elsner of Florida State University says this is to be expected. His research stated in 2008 that there was an upward trend in the intensity of the most intense tropical cyclones. Rising ocean temperatures, as theory predicted, were driving the trend. And with oceans continuing to warm along with Earth’s climate since then, Elsner anticipated the continuing upward trend. New research published in the Bulletin of the American Meteorological Society confirms his prediction, finding that another 3.5 to 4.5 percent increase in intensity has occurred with the strongest tropical cyclones during the period 2007-19.
Globally, all basins show upward trends, Elsner says, with the North Atlantic and Western North Pacific revealing the steepest and most consistent upticks.

An Anticipated Increase in Earth’s Strongest Storms

GoniA little more than two weeks ago, Supertyphoon Goni blasted ashore in the Philippines with top sustained winds of 195 mph, becoming the strongest landfalling tropical cyclone on record. It topped STY Haiyan’s 190 mph land strike just seven years ago. With Hurricane Iota in the Caribbean explosively intensifying 100 mph in under 24 hours to reach Category 5 intensity Monday, it set a new record of five consecutive years of Cat 5 hurricanes in the North Atlantic tropical cyclone basin. Among the seven catastrophic hurricanes, starting with Matthew in 2016, were Dorian and Irma, packing 185 mph and 180 mph steady winds, respectively, with peak gusts well over 200 mph.

Goni is the latest formidable example of an increasing trend in tropical cyclone intensity. While Goni established a new landfall wind intensity record, Iota and other recent major hurricanes Eta, Zeta, and Delta set or challenged records for most intense hurricanes so late in the season.

PercentilesJames Elsner of Florida State University says this is to be expected. His research stated in 2008 that there was an upward trend in the intensity of the most intense tropical cyclones. Rising ocean temperatures, as theory predicted, were driving the trend. And with oceans continuing to warm along with Earth’s climate since then, Elsner anticipated the continuing upward trend. New research published in the Bulletin of the American Meteorological Society confirms his prediction, finding that another 3.5 to 4.5 percent increase in intensity has occurred with the strongest tropical cyclones during the period 2007-19.

Globally, all basins show upward trends, Elsner says, with the North Atlantic and Western North Pacific revealing the steepest and most consistent upticks.

Online Climate Science Course Keys Success to Frequent Forum Discussions

While colleges pre-COVID-19 were already designing and implementing courses for online instruction, the pandemic has pushed entire academic course offerings into this rapidly evolving virtual environment. A new article in the Bulletin of the AMS about an online climate science course for undergraduates, which was developed, offered, and honed to near-perfection based on postcourse surveys before coronavirus, provides this tip for virtual success: Have students engage each other often, one-on-one, in a discussion forum. The result, the instructors are finding, is improved comprehension, with a high percentage of students successfully absorbing and accurately communicating course material.

The online course is titled, “Climate and Climate Change,” and has been offered through the Department of Atmospheric and Oceanic Sciences (AOS) at the University of Wisconsin—Madison since 2013. “Students enrolled in this course learn the physical principles governing Earth’s climate and climate change within the broader context of societal impacts and global political considerations,” writes lead author Andrew M. Dzambo and colleagues in the article.

The goal, they write, is to improve student science literacy and address misconceptions by implementing a key learning tool: “the weekly discussion forum where students engage with each other while testing their own knowledge.” The result is an increased knowledge of climate science and the Earth-climate system, as the surveys showed.

The course—AOS 102—has been improved since its inception, and it grew in popularity when it was moved to summer semester in 2016. It expanded its capacity in 2018 to accommodate a growing waitlist of interested students. The course is delivered through weekly worksheets, quizzes, and a final project, but it’s the weekly forum discussions that instructors credit with students’ retaining and being able to discuss climate science.

In their article, the authors present a template of the course for implementation with other atmospheric or Earth-related science coursework:

Although the discussion forums were monitored by course instructors, every student engaged other students at least once a week and freely expressed their own fact-based feedback to one another. By having the majority of the weekly course grade centered around discussion forums and worksheet assignments, complemented with weekly quizzes and an independent final project, the majority of students leave the class with a fundamental understanding of climate science (as evidenced by the course surveys) and with the confidence that they feel well informed about climate change.

Syllabus

Welcome to the Sticky Skies: Costlier Air Travel in a Warmer, Wetter World

COVID-19 has upended air travel for now, but if the growth in global aviation resumes, one real drag on flying is going to be increasing energy needs due to global warming. New research published in the Bulletin of the American Meteorological Society by Diandong Ren (Curtin University, Perth) et al. shows that Earth’s warming climate is going to have an often overlooked—but costly—impact on the fuel consumption of airplanes. The reason: increased viscosity, or “stickiness,” of the air.

For starters, a warming atmosphere will expand and become less dense, reducing the lift produced by aircraft wings, which means planes must increase speed and burn more fuel to maintain carrying capacity. This disadvantage counteracts any fuel advantages of flying in thinner (less resistant) air. There are other small effects on engine efficiency. In all, there is some ambiguity about the direct effect of the warming atmosphere on fuel needs at cruising altitudes. But Ren et al. point to a much larger fuel impact due to increasing atmospheric viscosity.

In a warmer world, more water can evaporate into the air. The extra molecules of water increase the drag on aircraft and that in turn will cause planes to fight harder to cruise through the air, requiring additional fuel. The increasing drag turns out to be the dominant issue—and could become very expensive.

Fuel increaseRen et al. use an ensemble of 34 climate models to project that aviation fuel requirements by the end of the century could be an extra 160 million gallons per year due to viscosity, approaching an extra $1 billion per year in costs more than today in a scenario in which fossil fuel use is basically unabated.

The findings take account of regional and altitudinal variations in warming for different projections based on different amounts of emissions predicted. They also take into account the most trafficked flight paths, based on recent airline data. For example, some high altitude cooling at high latitudes would mitigate the effects of drag in near-polar routes, but few jets fly these paths. Flights at mid- to low-latitudes experience the biggest increases in drag—less than 2% per century, but enough to have  consequences in fuel usage. Overall, an air viscosity increase leads to about a 0.22% increase in fuel consumption by the year 2100 over 2010.

While these costs are still a small fraction of the total aviation fuel usage, they are yet another incentive for the industry to mitigate global warming through emissions reductions, as well as to pursue adaptations and efficiencies in aviation technology.

Keeping Score When Temperature Records Are the Expectation

Through July, 2020 has been on almost the same track as 2016: the two years had the hottest first seven months in NOAA’s 141 year dataset of global surface temperatures (land and ocean combined). Since 2016 turned out to be the hottest year on record, it might seem as if this fast start puts 2020 on track to set a new record, too, or to be a near miss. NOAA says it’s already “very likely” 2020 will be among the five hottest years on record.

But in the strange reality of ever rising global temperatures, it’s not so much the first half of the year that puts 2020 on the verge of a record. It’s the underlying trend of warming: 2020 was already on the verge on New Year’s Day.

As the new State of the Climate in 2019 released last week points out, the six hottest years in the last century and a half were…exactly the last six years, 2014-2019. Due to global warming, practically every year’s surface temperature is going to be a hot one. Just by showing up at the starting line, every year is a serious threat to set a new standard.

A paper recently published in the Bulletin of the American Meteorological Society puts this relentless streak of rising temperature expectations in terms of probabilities. There’s a greater than a 99% chance that most of the next 10 years through 2028 will be ranked among the top 10 warmest.

The study, by Anthony Arguez (NOAA/NCEI) et al. also finds an 82% chance that all years in the next decade will rank in the top 15 warmest years as global warming continues. Its authors suggest that record warm years are already “baked into the cake” of Earth’s global climate and that it would take “an abrupt climate shift for even a few years within the next decade to register outside the top 10 warmest years.”

To determine these odds, the researchers analyzed the monthly version of NOAA’s Merged Land Ocean Global Surface Temperature Analysis Dataset (NOAAGlobalTemp) to project annual global temperature rankings in the future. The ever-shifting expectations for global temperatures render the usual way of keeping tabs on the data—by comparing to 30-year normals—inadequate. So Arguez et al. formulated a new way to compare each year to surrounding years:

We introduce a “temperature score”  to help NOAA communicate the coolness or warmth of a given year relative to the long-term trend. We believe this is the first such projected ranking and temperature score currently produced operationally. Our objective is to use this tool to improve the communication of climate change impacts to the general public.

Top 10The temperature score from 1 (a very cold year) to 10 (very warm) is useful to distinguish between warmer and colder years relative to the long-term trend. As examples, the authors note that 2008 and 2011 were considerably cooler than surrounding years and below the overall trend, whereas 1998 and 2016 were not only the warmest years on record but were also notably warmer than surrounding years.

The study only includes average annual global temperatures through 2018. But as reported in the annual State of the Climate, 2019 ranks as the second or third warmest year on record (depending on your favored dataset), adding another year to the recent string of those warmer than any years back to the mid 1800s. The report notes that each successive decade since 1980 has been warmer than the previous. Arguez’ research suggests that not only will this continue but it will worsen dramatically.

This is a testament to the exceptional warmth experienced over the last few decades, punctuated by the last [5] years [2015–19], which have separated themselves from “the pack.”

We asked Arguez a few questions (more found in the latest print/digital issue of BAMS) about this work as well as about his background and what sparked his interest in meteorology.

Anthony_ArguezBAMS: What would you like readers to learn from your study of record global temperatures?

Anthony Arguez: I would like the general public to know that there is not a great deal of suspense that most years—if not all—over the next decade will likely register as top 10 years. In fact, the data suggest we should expect this, as it would likely take a pretty abrupt change to get us off this trajectory.

BAMS: How did you become interested in finding new ways to analyze the global temperatures and their trend?

AA: I feel like I’ve been staring at the annual global temperature time series continually over the past 15 years or so because it is just so interesting in many ways. I find it challenging and rewarding to develop methods to translate volumes of data into answers to specific questions posed by the general public. I’ve drawn inspiration from Nate Silver, whose penchant for expounding on and communicating the “signal” hidden in the “noise” informs the way I would like to see myself and fellow climate scientists communicate to the general public more effectively.

BAMS: What surprised you most in doing this work?

AA: I was very surprised that the ranking errors we found were so small! Before calculating the results, I had a gut feeling that these errors would be modest, but the mean absolute ranking error of ~2 spots a full 10 years out was well below anything I could have imagined. I clearly under-appreciated the predictability inherent in the observed upward trend when it comes to annual global temperature rankings.

BAMS: What was the biggest challenge?

AA: I think the biggest challenge we faced was that we were not aware of any similar operational products in existence (neither for projected rankings or global annual temperature scores), or of any papers that had characterized ranking errors in a similar fashion, so we were in uncharted territory to some extent.

BAMS: This isn’t the biggest climate challenge, or surprise, you’ve ever faced…

AA: I became interested in meteorology as a teenager in 1992 when Hurricane Andrew totaled my parents’ home in Miami, Florida.

 

New Assessment Is Confident Global Warming Brings Stronger, Wetter Tropical Cyclones

Even with a modest amount of global warming, future hurricanes will become nastier. They’ll push ashore higher storm surges, grow into superstorms like Hurricanes Dorian and Irma more often, and unleash inundating rains similar to Hurricanes Harvey and Florence more frequently.

That’s the assessment of published, peer-reviewed research in the past decade, according to an assessment by Thomas Knutson (NOAA) and colleagues, recently published in the Bulletin of the American Meteorological Society. It’s the second in a two part study conducted by the author team, 11 experts in climate and tropical cyclones (TCs). Part 1 found there are indeed already detectable changes in tropical cyclone activity attributable to human-caused climate change. Part 2, in the March 2020 BAMS online, project changes in the climatology of these storms worldwide due to human-induced global warming of just 2°C.

Highest confidence among the experts was in storm surge flooding. Rising sea levels due to warming and expanding oceans, responding to atmospheric warming and glacial ice melt, are already making it easier for hurricanes and even tropical storms to drive greater amounts of seawater ashore at landfall. And this will only worsen.

With CO2 levels climbing to about 414 ppm in March, as measured atop Mauna Loa in Hawaii, Earth is on track to reach a 2°C average global temperature increase by mid century. Already global average surface temperature has risen 1.2°C since the Industrial Revolution began.

In the assessment the authors have medium-to-high-confidence that rainfall rates in tropical cyclones will increase globally by 14% due to the increasing amount of water vapor available in a warmer atmosphere. They project a 5% global increase in tropical cyclone intensity along with an increase in the number of Category 4 and 5s ̶ although the range of opinions among the experts involved is 1-10%. In the Atlantic Basin, which includes the Caribbean Sea and Gulf of Mexico, the number of storms is projected to decrease while intensity as well as the number of intense hurricanes increases.

Other studies found that hurricanes will slow down, making them even more prolific rainmakers, among other changes. Authors of the new assessment discussed these additional changes, but cited less confidence in general and that different tropical basins around the world had different projections:

Author opinion was more mixed and confidence levels generally lower for some other TC projections, including a further poleward expansion of the latitude of maximum intensity of TCs in the western North Pacific basin, a decrease of global TC frequency, and an increase in the global frequency (as opposed to proportion) of very intense (category 4–5) TCs. The vast majority of modeling studies project decreasing global TC frequency (median of about −13% for 2°C of global warming), while a few studies project an increase. It is difficult to identify/quantify a robust consensus in projected changes in TC tracks across studies, although several project either poleward or eastward expansion of TC occurrence over the North Pacific. Projected TC size metric changes are on the order of 10% or less, and highly variable between basins and studies. Confidence in projections of TC translation speed is low due to the potential for data artifacts in the observed slowdown and a lack of model consensus. Confidence in various TC projections in general was lower at the individual basin scale than for the global average.

Summary of TC projections for a 2°C global anthropogenic warming. Shown for each basin and the globe are median and percentile ranges for projected percentage changes in TC frequency, category 4–5 TC frequency, TC intensity, and TC near-storm rain rate. For TC frequency, the 5th–95th-percentile range across published estimates is shown. For category 4–5, TC frequency, TC intensity, and TC near-storm rain rates the 10th–90th-percentile range is shown. Note the different vertical-axis scales for the combined TC frequency and category 4–5 frequency plot vs the combined TC intensity and TC rain rate plot. See the supplemental material for further details on underlying studies used.
Summary of TC projections for a 2°C global anthropogenic warming. Shown for each basin and the globe are median and percentile ranges for projected percentage changes in TC frequency, category 4–5 TC frequency, TC intensity, and TC near-storm rain rate. For TC frequency, the 5th–95th-percentile range across published estimates is shown. For category 4–5, TC frequency, TC intensity, and TC near-storm rain rates the 10th–90th-percentile range is shown.

AMS Goes for 100% Renewable Electricity for Its 100th Anniversary

by Bob Henson, AMS Councilor and Chair, AMS Committee on Environmental Stewardship (ACES)
Those of us involved with climate change in our professional lives—researchers, educators, authors, students—often feel the need to “walk the walk” in a demonstrable way. AMS is one of the world’s premier organizations involved with peer-reviewed research on our changing atmosphere, so it’s only fitting that the Society is finding ways to demonstrate its environmental bona fides in its own operations. For example, AMS has been a leader this past decade in working toward “green meetings.” An upcoming BAMS article will feature some green-meeting highlights, and a summary can also be found in the “About AMS” section of the AMS website.
Just in time for the Society’s 100th birthday, AMS has now ensured that the electricity supply in its offices in Boston and Washington, D.C., is effectively 100% renewable. The Boston shift involved working with the nonprofit Green Energy Consumers Alliance (GECA), a spinoff of Massachusetts Energy that works to maximize the use of renewables in the state’s electricity supply.
AMS recently finalized a renewable two-year agreement (retroactive to January 2019) to purchase Class I renewable energy certificates (RECs) from GECA. These certificates are equal to the full amount of electricity consumed at the AMS buildings at 44 and 45 Beacon Street. Each certificate mandates the production of one megawatt hour of renewable energy, documenting where, how, and when the energy (in this case, wind energy) was produced. In 2019, energy providers in Massachusetts were required to purchase in-state Class I RECs for 14% of all electricity they generate, a percentage that goes up each year by 1%. When entities such as AMS also purchase Massachusetts Class I RECs, it further stimulates the market for clean energy. In other words, Massachusetts Class I RECs don’t simply buy green energy that is already government-mandated; they actually promote the creation of new green-energy supplies within the state.
AMS Controller Joe Boyd worked with the AMS Committee on Environmental Stewardship (ACES) to research options for renewable energy at the Boston building and shepherded the final agreement with GECA.
“Given the Society’s strong commitment to environmental issues, it was natural that we include 100% renewable electricity sourcing to our efforts to maintain a small carbon footprint,” says AMS Executive Director Keith Seitter.
In Washington, AMS leases office space within the headquarters of the American Association for the Advancement of Science at 1200 New York Avenue NW. This building’s electrical supply is also effectively 100% renewable, via RECs that are purchased through a Constellation New Energy contract for transmission and generation. (The RECs do not include electric distribution, and the building also uses a small amount of natural gas.)
“ACES continuously strives to promote the Society’s environmentally progressive standards, complementing the research and efforts of AMS members. Thanks to felicitous timing, the Society is celebrating its transition to 100% renewable energy on its 100th anniversary,” says incoming 2020 ACES Chair C. Todd Rhodes (Coastal Carolina University).

It Used to Be "Inadvertent Climate Modification," Too

AMS Executive Director Keith Seitter sent a letter today to President Trump. It begins,

In an interview with Piers Morgan on Britain’s ITV News that aired Sunday, 28 January, you stated, among other comments:
“There is a cooling, and there’s a heating. I mean, look, it used to not be climate change, it used to be global warming. That wasn’t working too well because it was getting too cold all over the place”
Unfortunately, these and other climate-related comments in the interview are not consistent with scientific observations from around the globe, nor with scientific conclusions based on these observations. U.S Executive Branch agencies such as NASA and NOAA have been central to developing these observations and assessing their implications. This climate information provides a robust starting point for meaningful discussion of important policy issues employing the best available knowledge and understanding.

Read the whole letter here.
In response to the BBC interview, Bob Henson of Weather Underground’s Category 6 blog gave a detailed debunking of the President’s comments. It’s a useful read for those wanting to parse out the persisting misunderstandings about the climate change discourse.
One misconception Henson clarifies is the talking point about which came first, “climate change” or “global warming.”

The history of the phrases “climate change” and “global warming” is much more interesting than Trump gives it credit for. Researchers were using climatic change or climate change as far back as the early 20th century when writing about events such as ice ages. Both terms can describe past, present, or future shifts—both natural and human-produced—on global, regional, or local scales.

Climate change is a general term that has applied over the years to many forms of climate change. Per the AMS Glossary:

Any systematic change in the long-term statistics of climate elements (such as temperature, pressure, or winds) sustained over several decades or longer.

It applies to both natural and human-caused changes (and “anthropogenic climate change” gets its own Glossary entry).
Obviously, the term still applies. So does “global warming.” In 2018 already, “global warming” is in the title of several scientific papers accepted to AMS journals.
Henson traces the first usage of “global warming”—a term specific to the observed climate trend—to a paper by Wallace Broecker in the 8 August 1975 issue of Science.
This may indeed be the first paper to apply “global warming” to a changed worldwide condition, via carbon dioxide release. Broecker was writing in anticipation of this trend becoming an observed fact, surpassing the then-prominent cooling influence of dust and pollutants as

the exponential rise in the atmospheric carbon dioxide content will tend to become a significant factor and by early in the next century will have driven the mean planetary temperature beyond the limits experienced during the last 1000 years

The idea that the Earth would warm as a whole, if not in every locale or region, was not new at the time of Broecker’s paper. In 1971, the National Academy of Sciences had included an objective to study the “effect of increasing carbon dioxide on surface temperatures” in its report, “The Atmospheric Sciences and Man’s Needs” (summed up by Robert Fleagle in BAMS that year).
The term “global warming” itself appears in AMS journals at least five years before Broecker’s paper. Jacques Dettwiller addressed the means of collecting long term global temperature records in the February 1970 Journal of Applied Meteorology. Lamenting the difficulty of separating out urban heat island effects, Dettwiller advocated monitoring deep soil temperatures, which seemed to “afford a means to monitor the global increase in temperature during the first half of the 20th century.”
For our purposes, it’s a landmark paper in the way Dettwiller cited a 1964 paper in Monthly Weather Review by Stanley Changnon that used such techniques in rural Urbana, Illinois: Changnon, wrote Dettwiller, “was able to discern values for global warming….”
At the time, the “current” term for global warming or anthropogenic climate change through the greenhouse effect was actually, ”Inadvertent Climate Modification.” That was the title of a 1971 report by an international group of climatologists convened by MIT and the Royal Swedish Academies for a “Study of Man’s Impact on Climate.” It was one of the first large consensus reports to warn of sea level rise, polar ice cap melt, major Arctic warming, and more.
After nearly a half century of highly prominent scientific warnings, a word was indeed dropped from the climate lexicon because it no longer made sense. That word was “inadvertent.”
 

Withdrawal from the Paris Agreement Flouts the Climate Risks

by Keith Seitter, AMS Executive Director
President Trump’s speech announcing the U.S. withdrawal from the Paris Climate Agreement emphasizes his assessment of the domestic economic risks of making commitments to climate action. In doing so the President plainly ignores so many other components of the risk calculus that went into the treaty in the first place.
There are, of course, political risks, such as damaging our nation’s diplomatic prestige and relinquishing the benefits of leadership in global economic, environmental, or security matters. But from a scientific viewpoint, it is particularly troubling that the President’s claims cast aside the extensively studied domestic and global economic, health, and ecological risks of inaction on climate change.
President Trump put it quite bluntly: “We will see if we can make a deal that’s fair. And if we can, that’s great. And if we can’t, that’s fine.”
The science emphatically tells us that it is not fine if we can’t. The American Meteorological Society Statement on Climate Change warns that it is “imperative that society respond to a changing climate.” National policies are not enough — the Statement clearly endorses international action to ensure adaptation to, and mitigation of, the ongoing, predominately human-caused change in climate.
In his speech, the President made a clear promise “… to be the cleanest and most environmentally friendly country on Earth … to have the cleanest air … to have the cleanest water.” AMS members have worked long and hard to enable such conditions both in our country and throughout the world. We are ready to provide the scientific expertise the nation will need to realize these goals. AMS members are equally ready to provide the scientific foundation for this nation to thrive as a leader in renewable energy technology and production, as well as to prepare for, respond to, and recover from nature’s most dangerous storms, floods, droughts, and other hazards.
Environmental aspirations, however, that call on some essential scientific capabilities but ignore others are inevitably misguided. AMS members have been instrumental in producing the sound body of scientific evidence that helps characterize the risks of unchecked climate change. The range of possibilities for future climate—built upon study after study—led the AMS Statement to conclude, “Prudence dictates extreme care in accounting for our relationship with the only planet known to be capable of sustaining human life.”
This is the science-based risk calculus upon which our nation’s climate change policy should be based. It is a far more realistic, informative, and actionable perspective than the narrow accounting the President provided in the Rose Garden. It is the science that the President abandoned in his deeply troubling decision.