donsutherland1

Argo floats, satellite measurements of solar irradiance, satellite measurements of ice melt, etc. all provide data for measuring the energy imbalance.

Great point regarding the energy imbalance. The recent paper revealing the energy imbalance had an error bar of 0.12 w/m2. That the earth has already experienced dramatic and sustained warming is evidence of that imbalance. The idea that a significant imbalance might not exist (be an error) is implausible.

Thanks for sharing this personal account. I do remember some of the past discussions at Eastern on the topic of climate change. To be fair, even as the body of evidence at the time turns out to have been fairly substantial, there was much less access to research papers and data sets back then. I think that the biggest test for anyone intellectually is the capacity to change one’s view to fit the evidence. The easier and more destructive path is to filter or reject the evidence to maintain one’s view. Where one winds up based on the evidence is far more important than one’s starting point. The problem of climate change and its urgency is of even greater magnitude than what I had thought back then. IMO, with hindsight from what happened over the years, the skeptics never really had a body of scientific work on which to base their position. As each one of their hypotheses—bad temperature measurements, claims that the energy imbalance was an artifact of measurement limitations, the sun had caused the warming, the oceans were responsible, cosmic rays were to blame, etc.—were blown out of the water, the futility of their position was exposed. As that happened, they increasingly resorted to attacks on the climate scientists, with some even claiming that climate scientists are not real “scientists.” Their evasions of the issue grew more desperate. Today, their remaining shield is comprised of appeals to uncertainty in detail and appeals to hopeless complexity, along with labeling (attaching the prefix “catastrophic” to “AGW” to denigrate scientific understanding). Uncertainties exist. Nuances exist. Details at the smaller-scale e.g., cloud responses, are still not well understood (although in this area, early evidence also does not favor the skeptics given data on northward shifts in clouds and high clouds forming at higher altitudes). For all that, the scientific verdict is unambiguous and unequivocal: the observed warming is real and significant and anthropogenic greenhouse gases are the prime driver of this warming. There is no other plausible alternative explanation. Despite the lines of evidence in paleoclimatology (ice cores, coral, sediments, tree rings, pollen, leaf wax, etc.) and nature’s observed response to warming (shifting flora, receding glaciers, falling summer and annual Arctic sea ice extent, rising sea levels, increased frequency of extreme weather or fires), the reality is many of the loudest skeptics ignore all of this evidence. Many now principally found on Social Media (especially Twitter) have become prisoners of their own biases and wishes. Long story short, people who allow their thinking to evolve based on the growing body of evidence deserve credit. There is never any shame in one’s having changed or adjusted one’s positions in light of evidence. That is a courageous and enlightened intellectual approach. That’s what learning is. Defending and maintaining one’s positions despite the evidence—even when they are no longer sustainable in any reasonable examination of affairs—is the far worse course.

On the issue of oceans, here’s a link to a paper that was published earlier this year: https://link.springer.com/content/pdf/10.1007%2Fs00376-020-9283-7.pdf

Yes, there’s a lag. That’s why scientists refer to “committed warming.”

In a paper published in the Journal of Geophysical Research on August 20, 1988, Dr. James Hansen and seven co-authors wrote, "Our model results suggest that global greenhouse warming will soon rise above the level of natural climate variability." They explained that if the temperature "rises and remains for a few years above an appropriate significance level, which we have argued is about 0.4°C for 99% confidence (3σ), it will constitute convincing evidence of a cause and effect relationship i.e., a 'smoking gun,' in current vernacular.” Today, global temperatures are routinely more than 0.4°C above what they were in 1988. That forecast for greenhouse gas warming was arguably the greatest long-range weather or climate forecast ever made. In the research that built upon that work and new findings that followed, the world's climate scientists warned that adding heat to the global climate system would lead to more weather extremes (temperature, precipitation, drought, and storms). They warned that the consequences of such extremes would be severe. Last year, Europe experienced its worst heat waves in history. At the height of the extreme heat, Paris saw the temperature soar to a previously unthinkable 109°. Anchorage reached 90° for the first time on record in a summer that saw June, July, and August all set monthly records for warmth. This year, Siberia was gripped by exceptional warmth that saw the temperature soar to 100° within the Arctic Circle. Phoenix experienced its warmest summer on record. Death Valley registered a 130° temperature, which is likely the highest reliably recorded temperature in world history during the instrument record. Greater heat, more prolonged heat waves, and more frequent compound high minimum and maximum temperature extremes were forecast by the climate scientists. Those forecasts proved accurate. Australia's record-breaking fire season of summer 2019-20 was no fluke. The West Coast's current fire season, its worst fire season on record, which has already seen 2.3 million acres burned in California, is no random occurrence either. A growing body of scientific literature revealed the growing risk of a hellish trinity of heat, drought, and fire. In an act of responsible journalism, The Washington Post linked the raging West Coast wildfires to climate change explaining, "The wildfires come after a record-shattering heat wave and amid human-caused climate change that is heightening fire risks, along with temperatures, in the West." Such context is the lowest common denominator of sound journalism in the era of climate change. Imagine, for a second that seasonal forecasts for the winter ahead or summer ahead calling for one's preferred weather verified over and over and over again. One would hail those making the forecasts. Such acclaim has not been showered on the world's climate scientists. Yet, the level of skill described above in the hypothetical seasonal forecasts has actually been demonstrated by the world's climate scientists, at least as far as the cause of climate change and its big picture implications are concerned. They have been right over and over again. That public policy has been frozen does not detract from the outstanding results they have demonstrated from their work. The enormous body of evidence built by the world's climate scientists coupled with the lack of a body of evidence for alternative explanations of even a fraction of this evidence demonstrates that there is no reasonable explanation for the observed warming since the mid-20th century except for anthropogenic global warming (AGW). Human activities and the greenhouse gases emitted from those activities--not the sun, not the oceans, and not "hail Mary" appeals to cosmic rays--are the principal driver of the observed warming. The case for AGW has been proved in the scientific literature. AGW has been experienced by people in real life in the now annual or more frequent return of "once-in-a generation" or even "hundred-year" events. Human greenhouse gas emissions are now leaving behind the world in which humans first evolved and bestowing on future generations a completely different world in which humans might never have evolved. The scientific arguments are over. The scientific debate has ended. Society has a moral obligation to render the correct verdict based solely on the evidence before it. The case for AGW has been proved. It has been proved well beyond the threshold of "beyond a reasonable doubt." Now, concrete action must follow.

During 1971-2018, 89% of the earth's growing energy imbalance was stored in the oceans. That has led to rising oceanic heat content at all depths. Source: https://essd.copernicus.org/articles/12/2013/2020/essd-12-2013-2020.pdf With the earth experiencing a persistent positive energy imbalance (now +0.87 W/m^2), of which the overwhelming share is being stored in the oceans driving rising oceanic heat content at all depths, what would trigger a large-scale sustained oceanic cooling cycle? Such an event is not realistic as long as the energy imbalance persists.

I might be a bit pessimistic, but I suspect that it will take either the Millennial Generation or Generation Z to bring about the big changes needed. By that time, the societal commitment to even greater warming will already have been made by current policy choices. Tragically, the status quo has too much momentum at present. Generations preceding the Millenial Generation are, by and large, overly committed to the status quo. We are exceptions to that condition. These earlier generations see fossil fuels as an immutable part of the energy landscape. In contrast, at least the early opinion polling shows that the Millennials reject notions of a fossil fuel constraint. They don't see the industry as "untouchable." But for now, their political influence is limited. Historic experience reveals that societies can make great technological leaps over very short periods of time. Development of the atomic bomb, the technologies needed to reach and return from the moon safely, and the rapid emergence and development of the Internet and related technologies provide some examples. The energy sector, with some modest exceptions, has been relatively stagnant when compared against the above examples. Advances have been incremental e.g., how to extract hard-to-reach fossil fuels via fracking, etc., as opposed to the development of carbon free sources despite the companies' possessing enormous financial resources and engineering talent. Absent sustained and growing pressure for big and rapid change e.g., the kind of pressure present during the Manhattan Project, large parts of the energy sector could well remain a relative backwater. The Millennials and Generation Z will likely place increasing pressure for big breakthroughs through their societal choices. Both see addressing climate change as the biggest and most urgent issue confronting their generation. As their political clout grows, they will likely favor policy changes that require fossil fuel companies to pay for externalities associated with carbon pollution--and yes, pollution is the correct term, as excessive dumping of even naturally-occurring compounds can be hazardous to the environment. Once that happens, the balance of incentives will shift toward carbon-free energy. Ensuring that fossil fuel producers pay the full costs of their carbon pollution would probably accomplish far more than simply eliminating tax expenditures that help incentivize such production. One complicating factor is that certain countries such as Russia and Saudi Arabia, even if the U.S. changes its policy course, may stubbornly persist in producing and marketing fossil fuels. They may even subsidize them to a greater extent than exists today to keep such energy sources viable.

.87. Small typo on my part, but a huge problem were the mistyped figure accurate.

The idea that anthropogenic greenhouse gases have become the dominant forcing driving the observed warming is settled. That’s a fairly narrow point. There is no compelling alternative explanation in the literature. That’s why the IPCC is considering upgrading its assessment to 99%-100% confidence in that idea. In the larger scheme of things, nuances and uncertainties exist. Questions about feedbacks persist. Finally, a newly published paper found that the earth’s energy imbalance has increased to +.87 W/m^2 in recent years. That may seem small, but it’s a very large imbalance.

Decades. As far back as the 1930s the risks associated with tobacco had become clear. https://www.ncbi.nlm.nih.gov/books/NBK294310/

I would hope that humanity would act to avert the worst of climate change.

Here’s the attribution study. https://www.worldweatherattribution.org/wp-content/uploads/WWA-Prolonged-heat-Siberia-2020.pdf At this point, at least within the scientific realm, the argument about climate change is a settled one. Anthropogenic greenhouse gas emissions are the dominant driver of the ongoing observed warming.

The findings in Mann’s paper were largely reaffirmed. https://ral.ucar.edu/projects/rc4a/millennium/refs/Wahl_ClimChange2007.pdf The body of evidence behind AGW is robust. There is no compelling alternative, much less one that has even a fraction of support in the literature that exists for AGW. Actually, I believe the issue isn’t that climate science hasn’t proved its case so to speak, but that those who reject the overwhelming evidence for AGW are demanding a level of certainty not expected from other fields or disciplines.

Thanks Bdgwx.

And a timely new paper on this topic: https://essd.copernicus.org/articles/12/2013/2020/essd-12-2013-2020.pdf

September 1-7 Update: Phoenix experienced its hottest summer on record. Following that, it experienced one of its warmest first weeks of September on record. With climate change, the intense heat of increasingly hot summers is lingering longer. Summer is now stretching into the opening week of September. September 1-7, 2020 Summary: Average high temperature: 108.9° (tied 2nd highest) Average low temperature: 85.9° (6th highest) Average temperature: 97.4° (tied 2nd highest) Since 1980, the 30-year moving average mean temperature for the first week of September has increased 4.3°. The summer mean temperature has increased a similar 4.0°. Table 1: Average Summer and September 1-7 Temperatures (30-Year Moving Average) September 1-7, 1928 was the first case during which the mean temperature reached 90° (90.0°). By 1995, the mean temperature (30-year moving average) reached 90° for the first time (90.1°). September 1-7, 2006, with a mean temperature of 88.7°, was the last case during which the mean temperature was less than 90° during the first week of September. The first week of September is now as warm as the typical summer was during the 1971-2000 period. Average low temperatures now come to 80° or above. The last time the first week of September saw a weekly mean temperature below 80° was 2009 when the average temperature was 79.6°. The average number of days on which the high temperature reached 100° or above and 105° or above has also increased in recent years. Table 2: September 1-7 Select Data (30-Year Moving Average) Since recordkeeping began in 1895, Phoenix has had 11 cases during which the mean temperature was 95.0° or above during the first week of September. Eight (73%) of those cases occurred during 2000 or later. Six (55%) of those cases occurred during 2010 or later. September 4-6, 2020 was the hottest three-day period on record in September: Mean Temperature: 100.5° (highest on record) Mean High Temperature: 114.0° (highest on record) Mean Low Temperature: 88.7° (2nd highest on record; record: 89.3°, September 5-7, 2019) Table 3: Record High Maximum Temperatures Table 4: Record High Minimum Temperature Just as summer 2020 provided a foretaste of the kind of summers that are expected to become routine by 2050 on account of climate change, the first week of September 2020 offered a glimpse into the future of the staying power of summer's most intense heat under the evolving climate regime.

I agree. Dante’s Divine Comedy would be a great fit. Hopefully, humanity will summon the strength, the courage and the foresight to finally take on the climate change challenge. The siren call of climate change denial must be ignored for that to happen. In many ways, just as society would not tolerate open dumping in reservoirs and rivers, it should adopt a similar stance toward open dumping of greenhouse gases into the atmosphere. Obviously, a transition will be needed, but society has made great technological leaps before when faced with enormous challenges. There’s no reason to believe that isn’t possible today.

From the Yale Climate Connections blog: Like a modern-day Ebenezer Scrooge escorted by the Ghost of Summers Yet to Come, California is catching a glimpse of its future summer weather. The view is a hellish one. Within a two-week span in August, California saw: – the “fire tornado” just north of Lake Tahoe – 130 degrees Fahrenheit heat in Death Valley, which may be the hottest temperature ever reliably recorded on Earth – a largely dry thunderstorm with 11,000 lightning strikes across California over 72 hours, igniting more than 300 wildfires, including two of the three largest ever recorded in the state (and still growing), creating the worst air quality in the world – one million acres burned in California in 2020 with 4 months to go in fire season – tens of thousands of people evacuated from their homes as the fires drew near – rolling power blackouts during a record heat wave – gray, unhealthy air. A blood red sun. Flakes falling from the sky, coating everything below in a layer of white… not snow, but ash. These ghastly scenes all bear links to climate change, and as a result, climate scientists expect them to occur more frequently in the future as global warming continues to raise temperatures and dry the landscape. https://yaleclimateconnections.org/2020/08/climate-change-is-worsening-californias-hellish-wildfires/

In its coverage of the extreme heat, the Los Angeles Times had a fairly lengthy discussion of climate change. https://www.latimes.com/california/story/2020-09-05/heat-health-risks This linkage to climate change provides important context for the newspaper’s readers and the general public. The Washington Post also provide climate change-related context when discussing California’s fires and extreme heat. The New York Times did not, depriving its readers of important insight into the events.

2020 was the 11th summer on record with a mean temperature above 94.5 degrees in Phoenix. It also became the 6th out of those 11 summers to see the 9/1-6 period wind up warmer than the entire summer average. All of those six summers with a warmer start to September occurred 2000 or later and four occurred 2010 or later. What this means is that the intense heat of exceptionally warm summers now has a tendency to last a little longer than had been the case in the past.

It’s not hubris. It’s a conclusion based on the evidence. Here’s one study that shows historical temperature trends, the trends that would have occurred only with natural forcings, and those that would have occurred only with anthropogenic forcings. The relevant charts are on page 8 of the paper. https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/jgrd.50239

When greenhouse gases are omitted, the observed ongoing warming cannot be replicated. Only when such gases are included can the observed warming be replicated. Gavin Schmidt, director of National Aeronautics and Space Administration’s Goddard Institute for Space Studies, said that scientists look at a lot of different things at once. “We have a very, very clear understanding that the amount of heat in the ocean is increasing—the ocean heat content is going up by a lot,” said Schmidt. “That implies that there must be an external change in the radiation budget of the earth—more energy has to be going in than leaving... To understand this rapid change in climate, scientists look at data sets and climate models to try to reproduce the changes that have already been observed. When scientists input only natural phenomena such as the sun’s intensity, changes in the Earth’s orbit and ocean circulation, the models cannot reproduce the changes that have occurred so far. “We have independent evidence that says when you put in greenhouse gases, you get the changes that we see,” said Schmidt. “If you don’t put in greenhouse gases, you don’t. And if you put in all the other things people think about—the changes in the earth’s orbit, the ocean circulation changes, El Niño, land use changes, air pollution, smog, ozone depletion—all of those things, none of them actually produce the changes that we see in multiple data sets across multiple areas of the system, all of which have been independently replicated.” In other words, only when the emissions from human activity are included, are the models and data sets able to accurately reproduce the warming in the ocean and the atmosphere that is occurring. https://blogs.ei.columbia.edu/2017/04/04/how-we-know-climate-change-is-not-natural/

There is literature about the lags namely where increasing solar insolation kicked off warming in the Northern Hemisphere and subsequent warming led to increases in CO2, which, in turn, amplified further warming. That humanity has engineered a “short cut” of sorts by dramatically and rapidly increasing atmospheric CO2 does not mean that (1) this increased CO2 won’t drive warming (CO2's properties found in physics and other empirical literature suggests that it should; the ongoing observed warming demonstrates that the expected warming is taking place) and (2) that one assumes the climate system is linear. No serious climate scientist has made such claims that I can find. The real question is why atmospheric CO2 levels consistent with the Pliocene should not produce warming perhaps of a similar magnitude? Global temperature are rising. The 2010s was the warmest decade of the instrument record (all major data sets). The 2020s will likely exceed that level of warmth.

A basic primer in slides by Paleoclimatologist Jessica Tierney: https://www.agci.org/sites/default/files/pdfs/lib/main/19s1_05_08_1800_Tierney_WOR_Aspen2019.pdf Dr. Tierney has done extensive research on earlier climate regimes e.g., the Eocene warming. She is the co-author of newly published paper on temperatures during the last ice age.