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Providing Insight
Into Climate Change
FoS Climate Science Newsletter - 2020

By: Ken Gregory, P.Eng.

 

CliSci # 322          2020-03-25

 

High Temperatures Reduce the Transmission of COVID-19

This paper investigates how air temperature and humidity influence the transmission of COVID-19 in 100 cities in China with more than 40 cases. The study found that both high temperature and high relative humidity significantly reduce the transmission of COVID-19, even after controlling for population density and GDP per capita of cities. The abstract says “This result is consistent with the fact that the high temperature and high humidity significantly reduce the transmission of influenza. It indicates that the arrival of summer and rainy season in the northern hemisphere can effectively reduce the transmission of the COVID-19.” The data used was before January 24 when China’s large-scale intervention in the spread of COVID-10 was announced so to study the influence of factors under natural condition. High temperatures and humidity reduce the transmission of influenza because Influenza viruses are more stable in cold temperatures and respiratory droplets that contain viruses remain airborne longer in dry air. Cold and dry weather can also weaken the hosts’ immunity. These factors also apply to the COVID-10 transmission. The paper presents an equation that gives the “severity of infectiousness”, R. One degree Celsius increase in temperature and one percent increase in relative humidity lowers R by 0.0383and 0.0224, respectively. Using Calgary’s climate data, the R value in July is 79% of that in March. In Tokyo, the R value with the normal summer climate (during the cancelled Olympic Games) is 52% of that in March.

So, why don’t climate change economic models include a reduction of respiratory illnesses like influenza as a benefit of global warming?

 

Climate Alarmist Claim Rebuttals

A website called Alarmist Claim Research (ACReseach) presents a series of rebuttals of the 12 most common climate alarmists’ claims such as those made in the recently released [USA] Fourth National Climate Assessment Report. The authors of these rebuttals are all recognized experts in the relevant fields. For each alarmist claim, a summary of the relevant rebuttal is provided below along with a link to the full text of the rebuttal, which includes the names and the credentials of the authors of each rebuttal. The rebuttals show that: Heat Waves – have been decreasing since the 1930s in the U.S. and globally; Hurricanes – this decade just ended as the second quietest for landfalling hurricanes and landfalling major hurricanes in the U.S since the 1850s; Tornadoes – the number of strong tornadoes has declined over the last half century; Droughts and Floods – There have been no statistically significant trends; and 8 other rebuttals.

 

Climate Models: Russia Good, Canada Bad

The Russian climate model INM-CM4 is the only climate model that closely replicates the Hadcrut4 surface temperature record, as well as the satellite datasets. Dr. John Christy commented “The CMIP6 models … are also warming faster than the real world. They actually have a higher sensitivity than the CMIP5 models; in other words, they’re apparently getting worse! This is a big problem.” The CMIP6 models will be used for the next IPCC assessment report. The average equilibrium climate sensitivity (ECS) of all the CMIP6 models is 3.86 °C, up from 3.2 °C (per double CO2) in CMIP5. The Russian model INM-CM4’s ECS has declined from 2.1 in CMIP5 to 1.8 in CMIP6. Meanwhile, the Canadian climate model Can ESM2’s ECS has increased from 3.7 °C in CMIP5 to 5.6 °C, which is the highest of all 27 climate models. The largest difference between the two models in CMIP6 is the cloud feedback, which in the Russian model at -0.13 W/m2/°C and is +0.80 W/m2/°C in the Canadian model. Ron Clutz wrote “Once again the Good Model INM-CM4-8 is bucking the model builders’ consensus. The new revised INM model has a reduced ECS and it flipped its cloud feedback from positive to negative.”

 

Relative Sea-level Rise and Land Subsidence in Oceania from Tide Gauge and Satellite GPS

A paper published last month analysis the relative and absolute sea-level patterns in Oceania using 5 long-term tide gauges and the global positioning system (GPS) time series. Long-term tide gauge data is required to account for periodic oscillations. The tide gauges with more than 90 years of data are located in Australia, New Zealand and Honolulu, USA. The average relative rate of rise is +1.306 mm/yr., the average acceleration is +0.0049 mm/yr2, and the average absolute rate of rise is +0.125 mm/yr. The acceleration term implies that the sea level rise in 80 years, or by 2100, would be 0.39 mm/yr higher than now. The average relative sea level rise (SLR) includes 1.181 mm/yr of subsidence which is 90% of the relative SLR. The study also analysed tide gauge and GPS data for two locations without long-term tide gauges, and report that the absolute SLR of Tuvalu from 1977 to present is 0.16 mm/yr and the absolute SLR of Adelaide is 0.2 mm/yr.  The SLR pattern is consistent with the other long-term tide stations of the Pacific. The global SLR “is explained as a gentle recovery from the low temperatures of the Little Ice Age that was caused by the record low solar activity of the Maunder and Spörer Minima as well as volcanic activity and internal oscillations in the climate system. … This result is consistent with the land increase, rather than shrinking, of the Pacific atolls’ islands recently highlighted by other researchers”.

 

New Model Helps Explain Seasonal Variations in Urban Heat Islands

Scientists from Duke University have created a simple new model that how urban heat island effects vary across seasons. A news release describing the model says ”Their results could help cities in different climatic regions design heat mitigation strategies.” The model provides general insights into how seasonal changes in rainfall, solar radiation, and vegetation conditions of an urban environment affect the intensity and timing of surface urban heat islands at a city-wide scale. The urban to rural surface temperature differences are controlled by time lags between solar radiation, temperatures, and rainfall. Urban area, where impervious and heat-absorbing surfaces can limit the effect of evaporative cooling, often grows much warmer than the surrounding areas. In cities where rainfall is scarce during summer, the opposite effect can occur, with rural areas heating up and cities may experience one to two degrees cooler temperatures than their surroundings.

 

Global Crop Yields

One reader asked me about global crop yields. I plotted the crop yields of six major grains using data from the UN Food and Agriculture Organization. See my graph here. Based on the best fit straight line through each series, the average yields of the six grains have increased by a factor of 2.4.  Crop yields have increased due to many factors, including increasing temperatures, CO2 fertilization, increasing precipitation and technological change. So what does Wikipedia say about crop yields in the future? It says “Global warming could lead to an increase in pest insect populations, harming yields of staple crops like wheat, soybeans, and corn.” Pest insects do cause losses, but other positive factors, especially CO2 fertilization and technological change have greatly exceeded the losses as crop yields continue to increase.


 

CliSci # 321          2020-03-07

 

Friends of Science 17th Annual Event

Please join us for this special event on April 6, 2020 for “Freedom of Speech! NO Climate Emergency!” featuring Donna Laframboise - Investigative Journalist and Dr. Roy W. Spencer - Principal Research Scientist at the University of Alabama at Huntsville. Doors open at 5:45 pm. The event includes a buffet dinner. Donna will speak on "Climate Activists Want Your Freedom" and Roy will explain “10 Reasons Why there is No Climate Emergency". Deadline to order tickets here is March 27, 2020.

UPDATE: This event is cancelled and will be rescheduled.

 

Coral Reefs in Turks and Caicos Islands Resist Bleaching Event

A study of the corals on Turks and Caicos Islands in the Caribbean from 2012 to 2018 found that 35 key coral species remained resilient during a 2017 global coral-bleaching event. The study found that corals that experienced bleaching quickly recovered. A EurekAlert news release said "Boulder-type corals on the Turks and Caicos Islands demonstrated no significant bleaching as a result of the peak thermal stress in late 2015," said Abby Knipp.  … Plate-type corals did suffer bleaching, but they quickly rebounded. Their pigmentation levels were back to normal within months of the anomalously high thermal stress." Pigmentation of the boulder corals was darker in 2017 than in 2014, suggesting these corals were even healthier after rebounding from the heat stress, Knipp said. "We were surprised that apparent healing and darkening could happen so fast," she said.

 

February Global Sea Ice Area

The best fit trend of the February global sea ice area over the satellite era, 1979 to 2020 is -0.32%/decade. See graph here. This is a tiny, insignificant decline. The February global sea ice area was 14.7 million km2, which is the highest since 2015. The Arctic trend was -0.093 million km2/decade while the Antarctic trend was +0.045 km2/decade.

 

Rapid 18th Century Sea Level Rise of North America’s Atlantic Coast

A study led by the University of York shows that there was a period of rapid pre-industrial sea-level rise of 2 to 3 mm/yr along the Atlantic coast of North America. The sea-level rise was entirely natural and related to the North Atlantic Oscillation, a natural atmospheric oscillation. The researcher produced a sea level reconstruction derived from microscopic fossils found in salt-marsh sediments. Scientists say salt-marshes are good "archives" of sea levels as they contain several metres of sediment which contains data going back hundreds of years. This 18th century sea-level rise was during the Little Ice Age and it wasn’t known before.  The study was described in a news release by EurekAlert. Lead author Gehrels said "To find out what global warming is doing to sea levels today we need that base level from historical times.” The study suggests that current sea level rise along the Atlantic coast of North America might be partially due to natural processes in the climate system.

 

A 5680-Year South America Tree-ring Temperature Record

A paper published in Quaternary Science Reviews presents a 5680-year tree-ring temperature record and demonstrates that solar forcing persistently influences temperatures at multi-centennial timescales. The study found that recent warming is not exceptional in the context of the last five millennia in southern South America. The reconstruction over 3700 BC to 2009 AD is the longest record for the Southern Hemisphere. The record shows two major warm periods of 3140 to 2800 BC and 70 BC to 150 AD, which coincide with no glacier advances. These periods also coincide with positive anomalies of solar irradiance. Spectral analysis show “show remarkable coincidences between the long-term cycles in our temperature record and the TSI reconstructions”. Reconstructed temperature changes at inter-decadal time scales is mainly related to internal climate variability of the Pacific Ocean, including El Niño Southern Oscillation (ENSO) and longer oscillations. The temperature reconstruction was adjusted to remove the CO2 fertilization effect on tree-growth for the 1800 to 2009 period.

 

Radiation Records Show that Declining Cloud Cover was the Main Driver of Warming

A paper published in January 2020 shows that most of the warming since 1980 was due to changes in cloud cover and that cloud cover changes affected temperatures much more than temperatures affected cloud cover. The energy balance of the Earth is the difference between the incoming shortwave (SW) radiation from the Sun net of reflected radiation, and the longwave (LW) radiation from the Earth emitted to space. Changes to SW radiation caused mainly by cloud changes had a much larger effect on the energy balance than changes in LW radiation. The authors used radiation data from the MERRA-2 reanalysis product from NASA and cloud data from the International Satellite Cloud Climatology Project. A statistical analysis of the data shows “that shortwave radiation is the main driver in the dynamics and plays a major role in the energy balance by affecting the longwave radiation field, while the information flux from longwave to shortwave radiation is marginal.” The analysis relies on the fact that changes in cloud cover changes the SW radiation almost instantly while the LW radiation changes are slower. The paper did not mention cloud feedbacks, but the analysis suggests that decreasing cloud cover was due to natural processes, rather than due to increasing temperature caused by greenhouse gases.

 

Carbon Dioxide Emissions Grow More Slowly Than Models Predict

Dr. Roger Pielke, Jr. published an article in Forbes, which compares the emissions scenarios of the fifth (AR5) and sixth (AR6) assessment report of the IPCC to the actual data. He wrote “Specifically, real-world observations of carbon dioxide emissions from 2005 to 2017 grew at a slower rate than 83% of AR5 (Working Group 3 baseline) scenarios and 73% of AR6 (SSP baseline) scenarios. … The divergence between the real-world observations of carbon dioxide emissions and the baseline scenarios of the IPCC is expected to widen over the next several decades. According to projections of major energy outlooks, by 2040 carbon dioxide emissions (from FF) may fall below the entire range of IPCC AR5 and AR6 baseline scenarios, even assuming that no new major climate policy efforts are undertaken between now and then.”


 

CliSci # 320          2020-02-22

 

Causes of Higher Climate Sensitivity in CMIP6 Models

A paper published last month finds that the temperature response to an abrupt quadrupling of atmospheric carbon dioxide has increased substantially in the latest generation of global climate models. This is primarily because low cloud water content and coverage decrease more strongly with global warming, causing enhanced planetary absorption of sunlight—an amplifying feedback that ultimately results in more warming. Differences in the physical representation of clouds in models drive this enhanced sensitivity relative to the previous generation of models. The equilibrium climate sensitivity (ECS) of the 27 global climate models range from 1.8 to 5.6 °C and exceeds 4.5 °C in 10 of them. The multi-model mean ECS has increase from 3.3 °C in CMIP5 to 3.9 °C in CMIP6. The non-cloud feedbacks are essentially unchanged between the two sets of models. The increase in the cloud feedbacks is due primarily to the short-wave or albedo component. Clouds decrease in area more in CMIP6 than in CMIP5 in response to a temperature increase, reducing albedo and allowing more sunlight in to warm the surface. Cloud cover area has indeed declined from 1986 to 2001, but this may be partly or primarily due to solar effects, rather than due to increasing temperatures.

 

A Climate Modeller Spills the Beans

Climate scientist Dr. Mototaka Nakamura published a book in Japanese on “the sorry state of climate science” titled “Confessions of a climate scientist: the global warming hypothesis is an unproven hypothesis” as reported in the Quadrant Online. From 1990 to 2014 he worked on cloud dynamics and forces mixing atmospheric and ocean flows on medium to planetary scales. Nkamura wrote “These models completely lack some critically important  climate processes and feedbacks, and represent some other critically important climate processes and feedbacks in grossly distorted manners to the extent that makes these models totally useless for any meaningful climate prediction.” On clouds he wrote “Accurate simulation of cloud is simply impossible in climate models since it requires calculations of processes at scales smaller than 1mm.” Instead, the modellers put in their own cloud parameters.”

 

Climate Science and Economics Presentation at Medicine Hat Branch of APEGA

I gave an hour presentation to the Medicine Hat branch of APEGA (Association of Professional Engineers and Geoscientists of Alberta) on February 18, 2020. The presentation was well received. I show evidence that the climate sensitivity to CO2 increases is low and that the social cost (benefit) of CO2 is net negative, meaning the CO2 emissions are net beneficial so fossil fuel usage should not be taxed. A PDF file of the slides is here.

 

Responses of Hail and Storm Days to Climate Change in the Tibetan Plateau

The Tibetan Plateau experiences the greatest hail frequency and also has one of the most frequent occurrences of severe storms in China. This study investigated the connection between climate change and severe storms and found that stormy days have decreased by 6.2%/decade since 1960 and days with hail decreased by 18.3%/decade in the region. The authors found that the decline of stormy days is strongly related to a dryer mid-troposphere since 1960. The reduction of hail is related to an elevation of the melting level and a weaker wind shear in a warming climate. The results “imply that there would be much less severe storm(s) if warming continues in the near future in the Tibetan Plateau.”

 

Plausible Scenarios for Climate Change: 2020-2050

Judith Curry wrote a post about scenarios for climate change that includes natural modes of climate variability, including volcanoes, solar and internal variability.  The climate model simulations used in the last IPCC report used greenhouse gas emissions scenarios that did not include natural climate change. “Internal variability” is primarily ocean circulation changes. Curry used the SSP2-4.5 emissions scenario issued for the forthcoming IPCC AR6 report, as it well matches the current emissions path. Curry gives two observationally constrained climate sensitivity estimates by Lewis (2018) and Grillett (2013) which give greenhouse gas (GHG) induced temperature increases of 0.35 °C and 0.47 °C, respectively, from 2020 to 2050. The forthcoming AR6 report estimates a potential solar induced cooling of 0.1 to 0.25 °C to 2050. Paleoclimate estimates of volcanic eruption of the last millennia suggest that the mean cooling by volcanoes is 0.12 °C by 2050. The Atlantic Multi-decadal Oscillation (AMO) is a major factor of interval variability and it is expected to shift to a cool phase within 15 years with a 50% chance of the shift occurring in the next 6 years. A moderate scenario predicts a 0.20 °C cooling by 2050 due to internal variability. Using the average of the GHG warming estimates of 0.41 °C, the combined median estimate of global temperature change 2020-2050 is +0.41 - 0.11- 0.10 - 0.20 °C  = 0.00 °C. Curry wrote “In summary, decade(s) during the period 2020-2050 with zero warming or even cooling should not be particularly surprising.”

 

Are Ocean Currents Speeding Up?

Dr. David Whitehouse reports on a new study that suggests that for almost 25 years, ocean currents have been speeding up, partly due to global warming. One headline said “Global warming is speeding up Earth’s massive ocean currents”. Whitehouse wrote “It contradicts previous studies that suggested that global warming will weaken ocean circulation, especially in tropical waters. This new study suggests the acceleration in ocean currents will be especially strong in tropical waters!” The authors claim that from 1990 to 2013, the energy of the world’s currents increased by some 15% per decade due to strengthening winds driving ocean currents. The velocity data used is from the ARGO diving buoys which have been operating since 2005.

 

A decade of variability on Jakobshavn Isbræ: Greenland’s Largest Glacier

A paper published last month shows that Greenland’s largest glacier has slowed and thickened substantially since 2016 in response to cooling sea temperatures. Atleast from autumn 2016 through spring 2019, winter thickening outpaced summer thinning, leading to net thickeningand elevations approaching those observed in 2010. “The elevation data show that although Jakobshavn Isbræ likely has the highest un-buttressed ice cliffs on Earth, at this point they do not appear to be subject to sustained catastrophic brittle failure. … there is substantial multi-decadal scale variability of ocean temperatures in Disko Bay [where the glacier terminates] that correlates well with the Atlantic Multi-decadal Oscillation (AMO) index. … whether Jakobshavn Isbræ can stabilize, at least temporarily, likely depends on whether a cycle similar to that of the last century produces an extended period (several more years to decades) of cooler waters in Disko Bay.”


 

CliSci # 319          2020-02-01

 

Climate Sensitivity, Agricultural Productivity and the Social Cost of Carbon in FUND

A paper by Dayaratna, McKitrick & Michaels evaluates the implications of recent empirical findings about CO2 fertilization and climate sensitivity on the social cost of carbon (SCC) in the FUND economic model. New satellite and experimental evidence suggests that the agricultural productivity gains due to CO2 fertilization are at least 30% greater than what is parameterized in the FUND model. The equilibrium climate sensitivity (ECS) probability distributions used are from the Lewis & Curry 2018 (L&C) and Christy & McNider 2017 (C&M) empirical studies, which gives ECS best estimates of 1.5 °C and 1.4 °C, respectively. Using a 5% discount rate, the 30% increase of CO2 fertilization and L&C ECS parameters, the FUND model calculates a best estimate SCC in 2020 of 2018US$-4.08/tCO2 and  there is a 0.78 probability that SCC is negative. Assuming that no CO2 mitigation policies are implemented, the SCC increases to 2018US$-3.43/tCO2 by 2050. Using a 3% discount rate and the C&M ECS, the best estimate SCC in 2020 is 2018US$‑6.85/tCO2. Using empirically estimated climate sensitivity, the FUND model indicates that CO2 is for all practical purposes not a negative global externality through mid-century. This means that carbon taxes and other policies that increase the costs of fossil fuels are harmful and counterproductive. The negative SCC implies that CO2 emissions should be encouraged, not taxed, because the social benefits of emissions exceeds the costs.

The ECS estimates used here assume that all of the warming was caused by human activity (greenhouse gases and aerosols), but a substantial portion of the measured warming was caused by natural causes and urban warming. Correcting the ECS for these effects would make the calculated SCC even more negative. As reported in CliSci # 317, an empirical study shows that the energy impact function in FUND is miscalibrated, and correcting this would substantially reduce the calculated SSC, making it even more negative.

 

Will Humanity Ever Reach 2XCO2? Possibly Not

Dr. Roy Spencer shows that a simple carbon cycle model that matches measured CO2 concentrations predicts the CO2 concentrations stabilizes at under a doubling of CO2 from pre-industrial levels when emissions remain constant after 2050. He wrote “The Energy Information Agency (EIA) projects a growth in energy-based CO2 emissions of +0.6%/yr through 2050. But translating future emissions into atmospheric CO2 concentration requires a global carbon budget model, and we frequently accept the United Nations reliance on such models to tell us how much CO2 will be in the atmosphere for any given CO2 emissions scenario. Using a simple time-dependent CO2 budget model forced with yearly estimates of anthropogenic CO2 emissions and optimized to match Mauna Loa observations, I show that the EIA emissions projections translate into surprisingly low CO2 concentrations by 2050. In fact, assuming constant CO2 emissions after 2050, the atmospheric CO2 content eventually stabilizes at just under 2XCO2.”

 

Friends of Science 17th Annual Event

Please join us for this special event on April 6, 2018 for “Freedom of Speech! NO Climate Emergency!” featuring Donna Laframboise - Investigative Journalist and Dr. Roy W. Spencer - Principal Research Scientist at the University of Alabama at Huntsville. Doors open at 5:45 pm. The event includes a buffet dinner. Donna will speak on "Climate Activists Want Your Freedom" and Roy will explain “10 Reasons Why there is No Climate Emergency".

Deadline to order tickets here is March 27, 2020. Early bird tickets are on sale until February 29, 2020. As climate dogma increases, your freedoms are lost, your kids are scared. Debunk it! Join us April 6th.

 

Contributions to Global Warming

I prepared two pie charts which show the contributions to global warming over two time periods, 1910 to 1980 and 1980 to 2018.  The contributions of greenhouse gases (GHG) are based on forcing estimate from NOAA and an estimated transient climate response of 0.85 °C, which corresponds to an equilibrium climate sensitivity of 1.0 °C for a doubling of CO2. This estimate is based on the energy balance calculations of Lewis&Curry 2015 and 2018, but adjusted to account for urban warming from McKitrick and Michaels 2007 (M&M) and the natural warming from the Little Ice Age. Aerosol forcing is estimated to have a net cooling effect, so this effect was added to the total measured warming to get the warming without aerosols, which was allocated to the factors that cause warming in the pie charts. The four components are CO2, non-CO2 GHG, urban warming, and solar effects. The urban warming was forecast to increase linearly from zero in 1920 such that the warming matched the M&M results. The solar component includes ocean oscillations such as the AMO, ENSO and the millennium cycle as the sun is the only energy source available that can drive these cycles. The GHG and urban warming was explicitly calculated and the solar component was estimated by difference. From 1910 to 1980, solar contributed 58% and CO2 contributed 26% of the global warming. From 1980 to 2018, solar and CO2 contributed 17% and 41%, respectively. Solar activity peaks in 1992 and has generally been declining since resulting in a lower contribution to warming.

 

50 Years of Global Hurricane Landfall Data

Dr. Roger Peilke published an article in Forbes which reported on a new historical time series of tropical cyclones that made landfall around the world. The article features a graph of 50 years of landfall hurricanes of strength 1&2, and 3 to 5 of the Saffir-Simpson hurricane scale. Tropical storms with wind speed of at least 119 km/h are hurricanes and those with wind speeds of at least 178 km/h are classified as major hurricanes of category 3 or greater. Peilke writes “There are a lot of ups and downs in the data, but no obvious trends. Last year saw 17 total storms, with 7 making landfall as major hurricanes.” From 1970 to 2019 there were 15.4 landfall hurricanes on average each year, including 10.4 categories 1&2 and 5.0 categories 3+.

 

Ocean Acidification Does Not Impair Coral Reef Fishes

As CO2 concentrations in the atmosphere increases, more CO2 is absorbed by the oceans causing the alkaline oceans to become more neutral. Contrary to some reports, this study comprehensively shows that ocean pH levels predicted by the end of the century have negligible effects on important behaviours of coral reef fishes. The abstract concludes “Together, our findings indicate that the reported effects of ocean acidification on the behaviour of coral reef fishes are not reproducible, suggesting that behavioural perturbations will not be a major consequence for coral reef fishes in high CO2 oceans.”

 

Attenborough’s Arctic Betrayal: New video

Dr. Susan Crockford, former adjunct professor and zoologist at the University of Victoria, released a new 13-minute video that shows “the strong polar bear component to the terrorization of the world’s children about climate change, which began for many youngsters in 2006 with the BBC and Sir David Attenborough’s commentaries about the dire future of polar bears – and continues to this day.” Children and young adults get climate change information from watching emotionally-charged and deceptive information about the Arctic through Attenborough’s productions. A press release issued by the Global Warming Policy Forum states: “It is the responsibility of teachers and parents to reassure these worried youngsters that polar bears and walrus are not suffering because of sea ice loss blamed on climate change.” In the BBC Frozen Planet series called ‘On Thin Ice’, Sir David Attenborough falsely claimed that polar bear numbers had been falling “in many regions”. The 2019 BBC’s ‘Seven Worlds, One Planet: Asia’ shows several ‘hungry’ polar bears driving walrus over the cliff, all falsely blamed on climate change. Attenborough is fed false information from activist NGOs and biologists. Crockford wrote “Sir David Attenborough never questioned his sources and neither has Greta. Both are out of touch with reality on what is happening in the Arctic and it has tarnished their outlook on life”.


 

CliSci # 318          2020-01-18

 

Early Holocene Temperature Oscillations Exceed Amplitude of Observed and Projected Warming in Arctic Svalbard Lakes

A paper published last month presents centennially resolved summer temperature reconstructions from sediments of three Svalbard lakes in the Arctic. The paper shows that early Holocene temperatures fluctuated between the coldest and warmest extremes of the past 12 thousand years, exceeding the range of instrumental observations and future projections. Peak warmth occurred about 10,000 years ago, with temperatures 7 °C warmer than today as more solar radiation and warm water reached the Arctic. The growing season temperatures increased by about 7 °C between 10.5 and 9.5 thousand years ago and peaked at values that were up to 7 °C warmer than at present. Comparison with model output shows that the amplitude of warming was on par with 21st century emission scenarios, but that temperatures rose much slower than today. The first major Early Holocene cooling episode is centered on 11,000 years ago and marked by a ~3.5 °C growing season temperature decline. Between 9.5 and 8 thousand years ago, temperatures dropped in response to freshwater fluxes into the North Atlantic from melting ice. The reconstructions indicate multiple times in the Holocene, for hundreds of years at a time, summer temperatures in the Arctic were at times warmer than now, only to fall later to temperatures colder than those experienced in recent centuries. The presented records span the entire Holocene, placing variability in a 12,000 year context.

 

The Hotter-Drier “Climate Change” Myth

The news media, politician and celebrities are all saying, especially in Australia, that greenhouse gas induced climate change are causing a hotter, dryer world which leads to the wild fires in Australia. This is false. Blogger Joanne Nova wrote that a central canon of the theory of man-made global warming is that climate change leads to a hotter, wetter world. In fact, the multi-model 60°S to 60°N near global precipitation trend from 2005 to 2030 is an increase from 3.245 mm/day to 3.266 mm/day, an increase of 0.65% in 25 years. Nova presents six charts of precipitation at six cities and none of them show any drying trend. In Australia, the average precipitation of the 21st century was 1.4 mm/day according to the CRU TS4 dataset, and the trend from 1900 to 2019 is upward at 0.013 mm/day/decade. This proves that the often heard narrative that “climate change will make dry areas drier” is false. Nova asks “When will Australia’s climate scientists correct the politicians and celebrities who benefit from making false claims?”

Larger fires are more frequent when soils are dry. NASA's Land Data Assimilation Systems produces a high quality dataset of soil moisture to 10 cm depth by integrating satellite and ground-based observational data products, using advanced land surface modeling and data assimilation techniques. The measured soil moisture content is a key indicator of the forest fire potential that is related to climate. The soil moisture content in Australia has been increasing at 0.164%/decade since 1985. This suggests that climate change may be inhibiting forest fires in Australia.

 

Fuel and Poor Forest Management is the Main Factor in Australian Wildfires

Friends of Science published an open letter on its blog January 13 to the Poynter Institute and Facebook that states “Your International Fact Check Network project is misreporting the facts” regarding the issue of the Australian wildfires. The document attached to the letter includes comments from a forest fire expert who states that “Heat is proportional to the fourth power of weight of fuel. Doubling even a sparse fuel loading has a huge consequence for fire intensity.” He says in Australia, there is lots of coarse debris on the ground. Surface fuels that were previously herbaceous and cured grass, now replaced by accumulating leaf and bark nested in woody perennial shrubs. It is worse than just the biomass increase. Fuel bed bulk density is very low, and the resinous vegetation and debris makes for extreme combustibility. The worst stand structure is most likely closest to and in communities. Fire suppression methods and community structure and building codes that were adequate for the previous fire regime completely fail with these stand replacing fires. Properly applied to forestry wildfire risk management would save lives and property in any forested region of the world.

 

New 80-Year Deep-Ocean Temperature Dataset Compared to a 1D Climate Model

A new paper Cheng et al 2020 presents a dataset of 0-2000 m ocean heat content (OHC) from 1940 to 2019 that uses “optimum interpolation” to extend the geographic coverage of limited data. The ARGO network of floats has dramatically improved the global coverage as it was deployed 2001-2005. Dr. Roy Spencer updated his 1D model of ocean temperature with this dataset to match its warming trend over the 80-year period. The model includes El Nino and La Nina (ENSO) variability to capture year-to-year temperature changes. If it is assumed that all of the ocean warming was human-caused, the best fit to the data gives an equilibrium climate sensitivity (ECS) of 1.85 °C. Spencer says this is only about 50% of the ECS from climate models. Temperature changes in the oceans below a few hundred metres are very small and difficult to measure. The average ocean temperatures (0-2000 m) have warmed over the last 10 years by 0.036°C. Spencer wrote “the global energy imbalance (less than 1 W/m2) corresponding to such small rates of warming is much smaller than the accuracy with which we know the natural energy flows (1 part in 300 or so), which means Mother Nature could be responsible for the warming and we wouldn’t even know it.”

 

40% of Warming Since 1979 Is Due to Early Volcanic Cooling

Spencer used the same 1D ocean model to show that 41% of the ocean warming in the model was simply due to the two major volcanoes early in the record. The model is forced with RCP6 radiative forcings scenario which includes greenhouse gases, aerosols and volcanoes. The model also includes the observed history ENSO. The model was run with and without the volcanic aerosols that block sunlight. The trend of average sea surface temperatures changes from 0.090 °C/decade with volcanoes to 0.053 °C/decade without volcanoes.

 

Divergent Consensuses on Arctic Amplification Influence on Midlatitude Severe Winter Weather

Arctic amplification refers to the phenomenon that the Arctic warms more, or is more variable, than the global average. This paper says “Recently, there have been considerable advances in understanding the physical contributions to ‘Arctic amplification’, and progress has been made in understanding the mechanisms that link it to midlatitude weather variability.” Observational studies show that Arctic amplification is contributing to winter continental cooling. However, most modelling results show little connection between Arctic amplification and severe midlatitude weather. Divergent conclusions between model and observational studies continue to obfuscate a clear understanding of how Arctic amplification is influencing midlatitude weather.


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