by W. Crockett, Mar 14, 2023 in ClimateChangeDispatch
There is no scientific evidence that the minuscule 0.01% increase in atmospheric carbon dioxide (CO2) since 1780 has had any effect on the Earth’s average temperature.
Nonetheless, in the 1980s, a religious/political movement against man-made or anthropogenic CO2 arose.
It was driven by catastrophic predictions from a gaggle of impenetrable and undecipherable computer climate models operated by the International Panel on Climate Change (IPCC) and quickly metastasized into a worldwide mass movement with all the fervor of a new evangelical religion.
…
Composition of the Atmosphere: The tropospheric atmosphere is composed of 78% nitrogen, 21% oxygen, 1% argon, 0.4 to 4% water vapor, and several trace gases.
The largest trace gas is carbon dioxide at 0.041%, followed by methane at 0.0018%, and nitrous oxide at 0.0003%. The volume of atmospheric molecules is also expressed in terms of parts per million (ppm): nitrogen 780,000 ppm, oxygen 210,000 ppm, and argon 10,000 ppm.
Scientists have also speculated that water vapor constitutes something between 4,000 and 40,000 ppm, depending on time and location. By contrast, the trace gas CO2 has only 410 molecules per million (.041%); methane (CH4) has only a minuscule 1.8 molecules per million; and nitrous oxide (N2O) is only a barely detectable 1/3 molecule per million.
All atmospheric molecules create a blanket of heat that slows the loss of infrared radiation to space. The sun’s short-wave radiation passes through the troposphere generally unimpeded by nitrogen, oxygen, and argon molecules to the surface, which increases the kinetic motion (heat) of all impacted surface and atmospheric molecules.1
The increased molecular motion, in turn, increases full spectrum (blackbody) infrared radiation (IR) in all directions. All atmospheric molecules, including water vapor and CO2, take up the additional heat by conduction (contact), from both the surface and surrounding atmospheric molecules.
by R. Pielke, Mar 17, 2023 in ClimateChangeDispatch
Next Monday the Intergovernmental Panel on Climate Change will release its so-called “Synthesis Report” which will integrate the findings of six different reports that it has released since 2014.
I have not participated in the IPCC nor have I seen the new report.
However, I have little doubt that one of the main issues that we will be discussing next week when the report is released will be the implausible climate scenarios that underpin much of the work of the IPCC over the past 9 years.[emphasis, links added]
Research I’ve been involved in — along with colleagues Matthew Burgess and Justin Ritchie — shows that theemissions scenarios that have guided the work of the IPCC and the broader climate research community are widely off the mark.
In short, they are far too extreme, both in what they project for today and especially into the future.
Our work is part of a growing consensus in the literature about the implausibility of extreme climate scenarios — a consensus so strong that it was acknowledged in the most recent IPCC assessmentreports, even though it complicated their messages.
The ubiquity of out-of-date scenarios throughout recent IPCC reports and the underlying literature that is has assessed means that the IPCC Synthesis Report, summarizing its work since 2014, runs the risk of promoting out-of-date science.
Feel helpless when trying to assess the veracity of “climate doom is looming” claims? Don’t give up trying to understand the relevant basics because you don’t need to be a scientist to do so.
There is a rather simple way to get an idea about what this is all about. Even without a scientific background, most people have at least a good common sense. And that’s all it takes to get a grasp of how energy flows back and forth between earth’s surface and the skies.
Today in Part 5, we look at the linkage between the allegedly CO2-driven rise of air and sea surface temperatures on the one side and the disconnect between these increases and their strangely weak to insignificant impact on rainfall and hurricane intensity”.
Variability of cloud effects vs “greenhouse gas” effects
In the last chapter, we have seen that there are some discrepancies between the global warming trend as claimed by the official climate science and the local evolution of rainfall, which should be a direct consequence of higher temperatures since this causes more evaporation. This seems not to be the case e.g. for Germany, see Fig. 1:
by G. Dickie, Mar 16, 2023 in ClimateChangDispatch
Heatwaves unfolding on the bottom of the ocean can be more intense and last longer than those on the sea surface, new research suggests, but such extremes in the deep ocean are often overlooked.
A team of scientists with the U.S. National Oceanic and Atmospheric Administration has conducted the first assessment of marine heatwaves along North America’s continental shelves.
They found that these bottom heatwaves ranged from 0.5 degrees Celsius to 3C warmer than normal temperatures and could last more than six months — much longer than heatwaves at the surface.
“We simply don’t have a ton of instruments on the ocean bottom along continental shelves,” said study co-author Dillon Amaya, an NOAA climate scientist. “The ocean is a powerful thing. It destroys instruments that we have in the water for too long.”
A lot of things have been going wrong for wind and solar fanatics lately. Biden, arguably the President with the greatest record of subsidizing unreliable wind and solar in America’s history, had his chance to bring down energy prices with his solar panels and wind turbines. Instead, he delivered the spectacle of the US Secretary of State crawling to the Saudis, begging for access to their oil, oil which could have been delivered by the Keystone Pipeline and other petroleum projects the Biden administration sabotaged.
The measures Britain and Germany have taken to avert catastrophe in the face of Russian gas supply disruption, and the utter failure of the climate alarmist’s energy programmes to deliver, are beyond embarrassing. Germany is bulldozing villages, old growth forests, even a wind farm to dig up coal to avoid further deindustrialization caused by their maniacal reliance on intermittent wind and solar. Britain deferred decommissioning her decrepit coal plants. Just as well, Britain needed those coal plants again just last week.
With the promises of the climate religion wearing thin, and climate concern faltering in the face of mortgage stress and soaring energy bills, perhaps this Rasmussen poll is what it appears to be – an early indication of a sea change in public opinion concerning climate change and climate action.
by D.W. Crockett, Mar 14, 2023 in ClimateChangeDispatch
There is no scientific evidence that the minuscule 0.01% increase in atmospheric carbon dioxide (CO2) since 1780 has had any effect on the Earth’s average temperature.
Nonetheless, in the 1980s, a religious/political movement against man-made or anthropogenic CO2 arose.
It was driven by catastrophic predictions from a gaggle of impenetrable and undecipherable computer climate models operated by the International Panel on Climate Change (IPCC) and quickly metastasized into a worldwide mass movement with all the fervor of a new evangelical religion.
As Eric Hoffer observes in his book, The True Believer, “Mass movements can rise and spread without belief in God, but never without belief in a devil.”
In this new “doomsday” mass movement, millions of people truly believe that man-made CO2 is a modern-day devil that will cause glaciers to melt, seas to rise, and coastlines to submerge. They also believe that mankind can, and must, save the planet from this catastrophe by reducing emissions of the devil CO2 to net zero.
Those who don’t believe are labeled “climate deniers,” a derogatory reference to those who deny that the Nazis perpetrated the Holocaust.
Unfortunately, most politicians in the U.S., Canada, and Europe, as well as the press and heads of many large corporations have blindly joined this Anthropogenic Global Warming (AGW) religion to stamp out the CO2 devil.
Global climate models (GCMs) from the sixth Coupled Model Intercomparison Project Phases (CMIP6) have been employed to simulate the twenty-first-century temperatures for the risk assessment of future climate change. However, their transient climate response (TCR) ranges from 1.2 to 2.8 °C, whereas their equilibrium climate sensitivity (ECS) ranges from 1.8 to 5.7 °C, leading to large variations in the climatic impact of an anthropogenic increase in atmospheric CO2 levels. Moreover, there is growing evidence that many GCMs are running “too hot” and are hence unreliable for directing policies for future climate changes. Here, I rank 41 CMIP6 GCMs according to how successfully they hindcast the global surface warming between 1980 and 2021 using both their published ECS and TCR estimates. The sub-ensemble of GCMs with the best performance appears to be composed of the models with ECS ranging between 1.8 and 3.0 °C (which confirms previous studies) and TCR ranging between 1.2 and 1.8 °C. This GCM sub-ensemble is made up of a total of 17 models. Depending on the emission scenarios, these GCMs predict a 2045–2055 warming of 1.5–2.5 °C compared to the pre-industrial era (1850–1900). As a result, the global aggregated impact and risk estimates seem to be moderate, which implies that any negative effects of future climate change may be adequately addressed by adaptation programs.However, there are also doubts regarding the actual magnitude of global warming, which might be exaggerated because of urban heat contamination and other local non-climatic biases. A final section is dedicated to highlighting the divergences observed between the global surface temperature records and a number of alternative temperature reconstructions from lower troposphere satellite measurements, tree-ring-width chronologies, and surface temperature records based on rural stations alone. If the global warming reported by the climate records is overestimated, the real ECS and TCR may be significantly lower than what is produced by the CMIP6 GCMs, as some independent studies have already suggested, which would invalidate all of the CMIP6 GCMs.
by P. Homewood, Mar 9, 2023 in NotaLotofPeopleKnowThat
The Met Office claims are derived from computer modelling based on the so-called RCP8.5 emissions scenario, the most extreme pathway for global greenhouse gas emissions, which the Met Office misleadingly describes as “plausible”.
In reality, most credible scientists regard RCP8.5 as implausible given that global emissions data and technological advances essentially rule it out. As a result, the Biden Administration has abandoned using this discredited worst-case scenario.
Moreover, the Met Office offers no empirical data in evidence that an increased trend in extreme rainfall events has actually been observed in line with their modelling. In fact some studies suggest the opposite may have occurred in recent decades.
Dr Benny Peiser, the director of the Global Warming Policy Foundation, called on the Met Office to withdraw its fatally flawed study: “The Met Office should withdraw this grossly misleading and baseless study which is undermining its scientific credibility and integrity and makes it look incompetent.”
Most of the 1100 Pacific and Indian Ocean islands have been growing, not shrinking in size, in the last half century.
Activists convinced humans are able to exert fundamental control over ocean dynamics claim the rates of sea level rise and modern climate change are so rapid and unprecedented that modern changes are dramatically affecting shoreline movement on low-lying islands.
But a new study (Kench et al., 2023) assesses the opposite may be true. Recent shoreline changes (±40 m/50 years) are “dwarfed” by the shoreline changes (±200 m/100 years) that occurred throughout previous centuries. Globally, here is nothing “unprecedented” about what has been occurring with reef island shoreline dynamics in recent decades.
Of the global database of 1,100 Pacific and Indian Ocean reef islands, the “dominant mode of response has been the expansion of islands on reef surfaces (>53%)” over the last half-century. Only 0.3% (3 of 1,100) of islands have experienced “total loss.” Similarly, Duvat (2019) found 89% of 709 global-scale islands have been either stable or growing in size since the 1980s.
Of the islands sampled for the study, none are older than 1,400 years. Before then, they were submerged beneath the sea due to the much higher sea levels of the past.
IPCC high-end sea level predictions for 2100 are “highly erroneous”.
Global warming alarmists like to claim that Pacific island nations are on the verge of disappearing – due to rising sea levels caused by polar ice melting due to global warming, which in turn supposedly is caused by rising concentrations of “heat-trapping” trace gas CO2 from the burning of fossil fuels.
These coral reef island nations risk going under real soon, unless we wean ourselves from fossil fuels soon, they say.
Coral reef island nations are emerging, not disappearing
But yesterday Kenneth here presented a new paper appearing in Nature, (Kench et al., 2023), which looks at whether the coral reef islands are in fact seeing unprecedented and undergoing accelerating physical changes that risk outrunning human adaptation measures. The authors analyzed the dynamics of a Maldivian reef island at millennial to decadal timescales.
Recent changes not unprecedented
The researchers found that “island change over the past half-century (±40 m movement) is not unprecedented compared with paleo-dynamic evidence”.
Nothing unusual is happening. The global data suggest that almost all islands are in fact growing, and not disappearing under water like climate alarmists mistakenly believe.
“Recent shoreline changes (±40 m/50 years) are ‘dwarfed’ by the shoreline changes (±200 m/100 years) that occurred throughout previous centuries,” the study’s authors write.
89% of all the globe’s islands are stable, or growing!
Moreover, just 4 years ago, another peer-reviewed publication appearing in a renowned journal found similar results: 89% of the globe’s islands and 100% of large islands have stable or growing coasts! According to Duvat, 2019:
“88.6% of islands were either stable or increased in area, while only 11.4% contracted. It is noteworthy that no island larger than 10 ha decreased in size. These results show that atoll and island areal stability is a global trend, whatever the rate of sea-level rise.”
Moreover, Khan et al (2018) found: “Prediction of 4–6.6 ft sea level rise in the next 91 years between 2009 and 2100 is highly erroneous.”
by J. Heller, Mar 7, 2023 in ClimateChangeDispatch
This article is in the tradition of articles that we have seen for decades saying we could look forward to snowless winters because of humans and our use of natural resources.
What is missing from every one of these articles is a direct link connecting oil consumption, CO2 content, or any other such thing with temperatures and snow. [emphasis, links added]
They cannot explain why we had a cooling period from 1940 to 1975, where essentially the same people who are warning of an existential threat of warming were warning of an existential threat that billions would die from an existential threat of a coming ice age.
Nearly half a gigaton of carbon (or 1.76 billion tons of CO2) was released from burning boreal forests in North America and Eurasia in 2021, 150 percent higher than annual mean CO2 emissions between 2000 and 2020, the scientists reported in a paper in Science.
“According to our measurements, boreal fires in 2021 shattered previous records,” said senior co-author Steven Davis, UCI professor of Earth system science. “These fires are two decades of rapid warming and extreme drought in Northern Canada and Siberia coming to roost, and unfortunately even this new record may not stand for long.”
The researchers said that the worsening fires are part of a climate-fire feedback in which carbon dioxide emissions warm the planet, creating conditions that lead to more fires and more emissions.
“The escalation of wildfires in the boreal region is anticipated to accelerate the release of the large carbon storage in the permafrost soil layer, as well as contribute to the northward expansion of shrubs,” said co-author Yang Chen, a UCI research scientist in Earth system science. “These factors could potentially lead to further warming and create a more favorable climate for the occurrence of wildfires.”
Davis added, “Boreal fires released nearly twice as much CO2 as global aviation in 2021. If this scale of emissions from unmanaged lands becomes a new normal, stabilizing Earth’s climate will be even more challenging than we thought.”
Analyzing the amount of carbon dioxide released during wildfires is difficult for Earth system scientists for a variety of reasons. Rugged, smoke-enshrouded terrain hampers satellite observations during a combustion event, and space-based measurements are not at a sufficiently fine resolution to reveal details of CO2 emissions. Models used to simulate fuel load, fuel consumption and fire efficiency work well under ordinary circumstances but are not robust enough to represent extreme wildfires, according to the researchers.
The Version 6 global average lower tropospheric temperature (LT) anomaly for February 2023 was +0.08 deg. C departure from the 1991-2020 mean. This is up from the January 2023 anomaly of -0.04 deg. C.
The linear warming trend since January, 1979 remains at +0.13 C/decade (+0.11 C/decade over the global-averaged oceans, and +0.18 C/decade over global-averaged land).
CNN are not the only media outlets to report on this years’ record low sea ice around Antarctica in apocalyptic terms, other media extremists are available. For Sky News it’s the accelerating melt of polar regions. For the BBC “There is now less sea-ice surrounding the Antarctic continent than at any time since we began using satellites to measure it in the late 1970s.” All this is technically true, but misleading. When it’s put into context one sees a different picture.
So let’s have a look at the actual satellite data of Antarctic sea ice collected monthly since 1979. The NSIDCgives two data sets for what it calls i) sea ice extent, and ii) sea ice area. So let’s examine both of them.
The first graphs is sea ice area, the second sea ice extent.
From the empirical data it is evident that there is hardly any change of sea ice over the 44-year time span. Since 2016 there is a dip with possibly more variability (of which more later), and the lowest month (February) does show a record low, but by hardly anything (and also look at the data for 1992). Does this actual data look like the beginning of the end to you? Where is CNN’s 90% loss or Sky News acceleration?
Millions of sq km; Source: National Snow & Ice Data Center
The December 1 to February 28 so-called meteorological winter has just ended and the latest data for the mean winter temperature are available for Tokyo and its island Hachijō-jima.
Tokyo winters have been cooling since 1984
With all the news about global warming, surely the decades long winter-trend for the city of Tokyo must be one of strong warming. Yet, looking at the mean DJF winter temperature trend for Tokyo going back 39 years using the untampered data from the Japan Meteorological Agency (JMA), we see a trend that has to surprise the global warming bedwetting dolts:
As the chart shows, instead of warming, winters in Tokyo have been cooling (modestly) since the global warming scare began in the 1980s. The average of the last 10 years have definitely been colder than the two preceding ten-year periods. Citizens in Tokyo who have been hearing warming doom for decades have in fact not experienced it. Where’s the warming?
by P. Homewood, March 1, 2023 in NotaLotofPeopleKnowThat
…
The new study uses computer models to assess Atlantic storms going back to 1949, and to peer into the future to see what storms will look like in 2100. The authors, climate scientists at Princeton University, found that the flood and wind risk posed by storms has steadily increased.
The problem will only get worse in the coming decades. “The frequency of intense storms will increase,” explains Ning Lin, a climate scientist at Princeton University and the lead author of the new study.
Most people don’t have a clear understanding of the greenhouse effect (GHE). It is not complicated to understand, but it is usually not well explained. It is often described as “heat-trapping,” but that is incorrect. Greenhouse gases (GHG) do not trap heat, even if more heat resides within the climate system due to their presence in the atmosphere. The truth is that after adjusting to a change in GHG levels, the planet still returns all the energy it receives from the Sun. Otherwise, it would continue warming indefinitely. So, there is no change in the energy returned. How do GHGs produce GHE?
GHGs cause the atmosphere to be more opaque to infrared radiation. As solar radiation heats mainly the ocean and land surface of the planet, GHGs absorb thermal emission from the surface at the lower troposphere and immediately pass that energy along to other molecules (typically N2 and O2) through collisions that occur much faster than the time it would take to re-emit the radiation. This warms the lower troposphere. The density and temperature decrease rapidly through the troposphere, so molecules are colder and more separated at the upper troposphere. Now GHGs have a chance to emit IR radiation so when they finally collide with another molecule, they are colder so GHGs have a cooling effect in the upper troposphere and stratosphere.
Because GHGs make the atmosphere more opaque to IR radiation, when they are present the emission to space from the planet normally does not take place from the surface (as happens in the Moon). Part of it still takes place from the surface through the atmospheric window, but most of it takes place from higher in the atmosphere. We can define a theoretical effective emission height as the average height at which the Earth’s outgoing longwave radiation (OLR) is being emitted. The temperature at which the Earth emits is the temperature at the effective emission height in the atmosphere. That temperature, when measured from space is 250 K (-23°C), not 255 which is the calculated temperature for a theoretical blackbody Earth. That temperature corresponds to a height of about 5 km, which we call the effective emission height.
A warming event that spans only one year, with decades of stable temperatures before and after, would not appear to align with rapidly rising human CO2 emissions or a gradually rising atmospheric CO2 concentration.
From 1958 to 2020, as CO2 rose from 320 ppm to 410 ppm, Greenland had a warming period of 1°C that lasted one year – 1994. Over the next 26 years (1994-2020) and spanning the years 1958 to 1993, there have been “relatively constant” temperatures across Greenland (Zhang et al., 2022).
These temperature trends appear to align much better with phases of the North Atlantic Oscillation (NAO), Greenland blocking indexes (GBI), and volcanism better than they do with any anthropogenic causal agents.
Fourteen years ago, a new climate myth was born. A grand solar minimum (GSM) was in the making that would not only reverse global warming but plunge the planet into a new Little Ice Age, surprising the warming alarmists and causing undue suffering. The time has come to bury that myth.
1. The origin of the myth
The deep solar minimum of 2008-2009 was a complete surprise to solar physicists. They did not know that solar activity could become so low because it had not occurred during the time of solar observations with modern instrumentation. In 2009, a solar scientist named Habibullo Abdussamatov published a paper in Russian in which he argued that the following years would see a major cooling based on the onset of a new GSM. His evidence was
The low solar activity of the then ongoing solar cycle (SC) minimum 23-24.
A bicentennial cycle in solar activity that supposedly decreased solar activity after 1600 and after 1800
The pause in global warming since 1998
Figure 1. From Abdussamatov 2009. “The Sun defines the climate”. Nauka i Zhizn, N1, pp. 34-42.
This prediction reached the West and became very popular, like any catastrophic prediction, actually. Articles about the arrival of a GSM proliferated on climate blogs, such as the one on WUWT: The ‘Baby Grand’ has arrived.
Other scientists, such as Livingston & Penn and de Jager & Duhau, joined Abdussamatov in 2009 in proposing the arrival of a GSM, though being more cautious about its climatic effects. It went so far as to threaten the global warming narrative at a time under assault from the Pause and Climategate. Thus, none other than Stefan Rahmstorf came to their defense saying that according to the models
“a new Maunder-type solar activity minimum cannot compensate for global warming caused by human greenhouse gas emissions.”
Despite being small, microbes, and especially bacteria, contribute a lot to the global carbon cycle — the movement of carbon in various forms through nature. Its level in the atmosphere, and so its influence on climate change, is controlled by a series of sources and sinks, such as respiration and photosynthesis respectively.
Now, new research from Imperial College London and University of Exeter scientists has shown that, when warmed, bacterial communities that have matured to co-operate release more carbon dioxide (CO2) than communities that are in competition with each other.
The results are published in Nature Microbiology.
Co-author Dr Tom Clegg, who led the theory development from the Department of Life Sciences (Silwood Park) at Imperial, said: “Our findings have far-reaching implications given the significant contributions that bacterial communities make to the carbon cycle. We show that changes in bacterial species interactions can rapidly and substantially increase the carbon emissions from natural ecosystems worldwide.”
Bacteria — like humans — respire, taking in oxygen and releasing CO2. Of the many factors that control their level of respiration, temperature is particularly important.
Bacteria form communities of different species in all habitable environments, including in soil, puddles, and in our guts. When communities first form, the bacterial species are often ‘competitive’, each trying to get the best resources.
by R. Pielke, Feb 13, 2023 in ClimateChangeDispatch
This is the latest post in an ongoing series, titled “what the media won’t tell you about…”, which is motivated by the apparent systemic inability of the legacy media to play things straight when it comes to extreme weather and disasters.
Climate change is real and important, but its importance is not an excuse for the pervasive climate misinformation found across the legacy media. [emphasis, links added]
Here are the previous installments in the series, which are among my most popular posts and which have gone unchallenged.
Today’s post focuses on U.S. tornadoes. This year so far has seen a lot of tornadoes — 178 were reportedthrough February 11th, the 2nd most since 2005 and well above the 2005-2022 mean of 66 to date.
For instance, after a tornado outbreak last month, the Associated Press reported that the tornadoes had been “juiced by climate change.”
Similarly, The Washington Post said that in the past it was difficult to tie tornadoes to climate change but now, “science is accumulating to support the linkage.”
Neither reported any of the data and science I share below. So, let’s take a look
by N. Scafetta, Feb 3, 2023 in MDPI, Earth Science
Global climate models (GCMs) from the sixth Coupled Model Intercomparison Project Phases (CMIP6) have been employed to simulate the twenty-first-century temperatures for the risk assessment of future climate change. However, their transient climate response (TCR) ranges from 1.2 to 2.8 °C, whereas their equilibrium climate sensitivity (ECS) ranges from 1.8 to 5.7 °C, leading to large variations in the climatic impact of an anthropogenic increase in atmospheric CO2 levels. Moreover, there is growing evidence that many GCMs are running “too hot” and are hence unreliable for directing policies for future climate changes. Here, I rank 41 CMIP6 GCMs according to how successfully they hindcast the global surface warming between 1980 and 2021 using both their published equilibrium climate sensitivity (ECS) and transient climate response (TCR) estimates. The sub-ensemble of GCMs with the best performance appears to be composed of the models with ECS ranging between 1.8 and 3.0 °C (which confirms previous studies) and TCR ranging between 1.2 and 1.8 °C. This GCM sub-ensemble is made up of a total of 17 models. Depending on the emission scenarios, these GCMs predict a 2045–2055 warming of 1.5–2.5 °C compared to the pre-industrial era (1850–1900). As a result, the global aggregated impact and risk estimates seem to be moderate, which implies that any negative effects of future climate change may be adequately addressed by adaptation programs. However, there are also doubts regarding the actual magnitude of global warming, which might be exaggerated because of urban heat contamination and other local non-climatic biases. A final section is dedicated to highlighting the divergences observed between the global surface temperature records and a number of alternative temperature reconstructions from lower troposphere satellite measurements, three-ring-width chronologies, and surface temperature records based on rural stations alone. If the global warming reported by the climate records is overestimated, the real ECS and TCR may be significantly lower than what is produced by the CMIP6 GCMs, as some independent studies have already suggested, which would invalidate all of the CMIP6 GCMs.
Claims the Swedish Scandes are unprecedentedly warm and tree-covered today “appear as large and unfounded exaggerations,” as the “climate and arboreal responses” of the last few decades “are still inside the frames of natural historical variation.” – Kullman, 2022 and Kullman, 2022a
Extensive birch forest fossils can be dated to the early- to mid-Holocene in northern Scandinavian regions, indicating these warmth-sensitive trees could exist in climates that are too cold for them to grow in today. This documents a much warmer period, “at least 3°C higher than during the past few decades,” 3000 to 10,000 years ago, or when CO2 was about 265 ppm (Kullman, 2022).
Contrary to modeler opinions, “there is little factual nourishment” to support modern projections that the Swedish Scandes will soon be returning to the subalpine birch forest climates of past millennia. The observed forest advancement in recent decades “is so small” that these modeling claims appear to be “unfounded exaggerations.”
“In the southernmost Swedish Scandes, pine has already “leap-frogged” over receding the birch forest-limit (Kullman 2014, 2019). That scenario would mimic the arboreal landscape during the early Holocene and shift to a landscape unseen for thousands of years (cf. Blűthgen 1942; MacDonald et al. 2008, Macias-Fauria et al. 2012). During that epoch, summer temperatures are inferred to have been at least 3°C higher than during the past few decades.”
“At the landscape level, the obtained changes contribute to a greater and lusher landscape, in contrast to the dire conditions during the Little Ice Age, more than 100 years ago (Kullman 2010, 2015). Currently, there is little factual nourishment to flourishing projections stating that a major part of Swedish alpine areas is on verge of transformation to subalpine birch forest (e.g. Moen et al. 2004). Apparently, climate and arboreal responses are still inside the frames of natural historical variation, as inferred by several authors (e,g. Hammarlund et al. 2004; Bergman et al. 2005; Kullman 2013, 2017a, b; Kullman & Öberg 2018, 2020).”
“Given that the current relatively warm climate phase continues, the subalpine birch forest belt may eventually recede and give way to a subalpine pine belt. The obtained modest forest-limit advancement is so small that flourishing model simulations of extensive birch forest expansion over most of the current alpine tundra appear as large and unfounded exaggerations.”
Tree remnants (trunks, cones, roots, etc.) found at northern Sweden mountain sites 500 to 700 meters atop where the 21st century tree line ends imply the early-Holocene (~13,000 to 7000 years ago) climate was significantly warmer than today in this region (Kullman, 2022a).
The temperature lapse rate for the Swedish Lapland region is 0.6°C/100 m. Accounting for glacio-isostatic uplift, this tree line elevation implies surface air temperatures were 3.6°C higher than today during the Early Holocene.
