Archives par mot-clé : Global Warming

How much human-caused global warming should we expect?

by Andy May, March 21, 2020 in WUWT


C3S20 asks, how much human-caused warming will occur if we do nothing, that is, continue “business-as-usual?” It’s unfortunate, but the IPCC, for all their work, do not adequately answer that question, their projections are all based on abstract “scenarios.” C3S20 break this overall question into five parts:

  1. What would greenhouse gas emissions (GHG) be, if we did nothing and continued normally?
  2. For each GHG, how do emissions relate to the change in atmospheric concentration?
  3. What would the global temperature be if GHG concentrations were at “preindustrial” levels?
  4. How sensitive are global temperatures to GHG concentrations?
  5. How much warming should we expect if we do nothing?

C3S20 tell us the Paris Agreement conclusion that we need to limit global warming to 2°C above preindustrial levels suffers from several unknowns.

  1. The preindustrial period is not formally defined. The preindustrial temperature and greenhouse gas level are not specified. In fact, several time periods, temperatures and GHG levels are used as “preindustrial” in the latest IPCC AR5 report.

  2. The assumptions that warming is bad and increasing levels of CO2 are bad, are not supported with any data. Numerous studies have concluded that some warming is good for humankind and additional CO2 is good for plants.

  3. The penultimate draft of AR5 identified the period 1850 to 1900 as the preindustrial baseline for CO2 and temperature. This was the end of the Little Ice Age, the coldest periodin the last several thousand years. Why use that period as a baseline (Luning and Vahrenholt 2017)? This is not explained, and the final draft of the report removed the reference to the 1850 to 1900 baseline.

  4. If the UNFCC and the Paris Agreement assume “climate change” and “Human-caused Climate Change” are synonymous, how do they explain that climate has change much quicker and much more dramatically many times in the past 13,000 years before human civilization began and well before industrialization?

Débattre du climat : quel contenu ?

by M. de Rougemont, 25 février 2020 in EuropeanScientist


Dès lors que la moindre critique est faite à propos de la doxa climatique son auteur se verra systématiquement désigné comme négationniste. Si, par-dessus le marché, ladite critique est pleine de bon sens, alors des caciques de ce système s’empressent de publier une tribune publique afin de mettre l’intru au pilori, évitant bien d’entrer en matière et de traiter des questions posées. Il s’agit de bien rappeler qui a droit à la parole et de rappeler aux non-sachants que le débat est clos car la cause est entendue. Un bizarre syndicat international de presse dictant la bien-pensance climatique a d’ailleurs décidé que laisser s’exprimer des voix critiques serait leur faire une part trop belle. La célérité et le ton de ces répliques témoignent pourtant d’une grande inquiétude car faire taire l’intrus n’a jamais été une manifestation de force et de tranquillité. Cela laisse même à penser que s’il y avait complot, ce serait plutôt celui destiné à éviter à tout prix la nécessaire dispute autour d’un sujet si important.

Nonobstant la clôture bien prématurée de ce débat jamais initié, il faut en décrire les chapitres qui devraient le composer.  Ce drame climatique se déroule sur trois scènes : scientifique, stratégique et politique.

SCIENCE ET PSEUDO-SCIENCE

Les données issues de moins de deux siècles d’observations directes, dont moins de cinquante ans par satellite, et de la paléoclimatologie nous enseignent les variations passées et certaines corrélations ou manques de corrélation. Ces données ne font pas l’objet de réfutations majeures et fondées. Un réchauffement est donc bien constaté depuis la fin du petit âge glaciaire coïncidant avec le début de l’ère industrielle ; il est de l’ordre de 0.8 à 1 °C avec des fluctuations dont certaines restent encore inexpliquées.

Continuer la lecture de Débattre du climat : quel contenu ?

Do We Really Have Only 12 Years to Live?

by Andy May, February 23, 2020 in WUWT


Why have uninformed celebrities and politicians been telling everyone, who will listen, we are all going to die in a climate catastrophe in 10 to 30 years? U.N. General Assembly President María Fernanda Espinosa Garcés of Ecuador warned us…

 

However, these absurd statements are not supported by even the most fanatical climate alarmists, like Kate Marvel (NASA), Gavin Schmidt (NASA), Katharine Hayhoe (Texas Tech), or Andrea Dutton (University of Florida) (link). The original inspiration for these statements came from a 2018 IPCC report entitled Global Warming of 1.5°C. Even the alarmist Scientific American does not think the world is ending in twelve years.

We will discuss this IPCC report below, but first let’s look at some critical evidence that is not in the report. As usual the IPCC dodges the current benefits of warming and additional CO2, so we need to fill in this gap.

A little over two years ago I posted an essay entitled “Calculating the Cost of Global Warming,” it did not calculate a cost, but discussed calculations made by others. Global warming and the increasing concentration of CO2 in the atmosphere are not existential threats to mankind or to nature. Global warming will not go “runaway,” this idea, discussed here, has been discredited by climate change skeptics and by climate alarmists alike (see here and here for examples). So, given that global warming and additional CO2 will not harm us, we are reduced to a discussion of the economic impacts and benefits, both positive and negative, of global warming and additional CO2.

 

Figure 2. A graph of CMIP5 global tropospheric temperatures (5-year averages) versus satellite and weather balloon observations. These predictions are for the Representative Concentration Pathway (RCP) 4.5, a moderate case. Source: House of Representatives report by Dr. John Christy.

Climate Change is not a problem: Unless we make it one.

by Martin Capages Jr., February 11, 2020 in WUWT


INTRODUCTION

As long as humans have been on Earth, they have been adapting to changes in regional climates. A regional climate is the average of the weather for a relatively long period of time, usually 30+ years, at a particular location on the planet. The natural periodicity of prolonged regional weather variations has been documented in various ways by humans for eons. For a comparison of human civilization in the northern hemisphere to Greenland ice core temperatures for the last 18,000 years see here. Some of the means of documenting changes in long term weather patterns, i.e. climate change, include crude prehistoric cave drawings of the animals and plants, paintings of frozen rivers (see Figure 1 of ice skating on the River Thames in 1684), and archaeological digs. There are also written records of climatic conditions as early as 5,000 years ago, perhaps even earlier. Ice, subsea, peat and lake bed cores are also used, for a more detailed discussion of the methods used see here and the links therein.

Figure 1. Ice skating on the River Thames in London in January 1684, during the Little Ice Age. Museum of London, link.

 

Continuer la lecture de Climate Change is not a problem: Unless we make it one.

Economic impact of energy consumption change caused by global warming

by P. Lange & K. Gregory, February 8, 2020 in ClimateEtc.


A new paper ‘Economic impact of energy consumption change caused by global warming’ finds global warming may be beneficial.

In this blog post we reproduce the Abstract, Policy Implications and Conclusions and parts of the Introduction, Results and Discussion. We encourage you to read the entire paper.

Abstract: This paper tests the validity of the FUND model’s energy impact functions, and the hypothesis that global warming of 2 °C or more above pre-industrial times would negatively impact the global economy. Empirical data of energy expenditure and average temperatures of the US states and census divisions are compared with projections using the energy impact functions with non-temperature drivers held constant at their 2010 values. The empirical data indicates that energy expenditure decreases as temperatures increase, suggesting that global warming, by itself, may reduce US energy expenditure and thereby have a positive impact on US economic growth. These findings are then compared with FUND energy impact projections for the world at 3 °C of global warming from 2000. The comparisons suggest that warming, by itself, may reduce global energy consumption. If these findings are correct, and if FUND projections for the non-energy impact sectors are valid, 3 °C of global warming from 2000 would increase global economic growth. In this case, the hypothesis is false and policies to reduce global warming are detrimental to the global economy. We recommend the FUND energy impact functions be modified and recalibrated against best available empirical data. Our analysis and conclusions warrant further investigation.

Gavin’s Falsifiable Science

by Willis Eschenbach, January 18, 2020 in WUWT


 

Folks are interested in why the temperature of the planet changes over time. That’s at the center of modern climate science. My theory, on the other hand, arose from my being interested in a totally different question about climate—why is the temperature so stable? For example, over the 20th Century, the temperature only varied by ± 0.3°C. In the giant heat engine that is the climate, which is constantly using solar energy to circulate the oceans and the atmosphere, this is a variation of 0.1% … as someone who has dealt with a variety of heat engines, I can tell you that this is amazing stability. The system is ruled by nothing more solid than waves, wind, and water. So my question wasn’t why the climate changes as it does.

My question was, why is the climate so stable?

And my answer is, there are a host of what are called “emergent phenomena” that arise when local temperatures go above some local threshold. They include the timing and strength of the daily emergence of the cumulus cloud field in the tropics; the development of thunderstorms; the emergence of dust devils when temperatures get hot; the action of the El Nino/La Nina pump moving warm water to the poles; and various “oscillations” like the Pacific Decadal Oscillation.

These emergent phenomena arise out of nowhere, last for some length of time, and then disappear completely. And acting together, they all work to prevent both the overcooling and the overheating of the planet. And as mentioned above, I say that these phenomena acted to reduce the length and the depth of the effect of the Pinatubo volcano. See my post called “When Eruptions Don’t” for another look at how the climate system responds to a decrease in incoming solar energy due to volcanic eruptions.

 

I originally published this theory in the journal Energy and Environment. I followed that up with a posting of the same ideas here at Watts Up With That in a post called The Thermostat Hypothesis.

Figure 2. Global stratospheric temperatures measured from space.

Climate models continue to project too much warming

by Dr. J. Lehr & J. Taylor, January 6, 2020 in CFACT


A recently published paper, titled “Evaluating the Performance of Past Climate Model Projections,” mistakenly claims climate models have been remarkably accurate predicting future temperatures. The paper is receiving substantial media attention, but we urge caution before blindly accepting the paper’s assertions.

As an initial matter, the authors of the paper are climate modelers. Climate modelers have a vested self-interest in convincing people that climate modeling is accurate and worthy of continued government funding. The fact that the authors are climate modelers does not by itself invalidate the paper’s conclusions, but it should signal a need for careful scrutiny of the authors’ claims.

Co-author Gavin Schmidt has been one of the most prominent and outspoken persons asserting humans are creating a climate crisis and that immediate government action is needed to combat it. Again, Schmidt’s climate activism does not by itself invalidate the paper’s conclusions, but it should signal a need for careful scrutiny of the authors’ claims.

The paper examines predictions made by 17 climate models dating back to 1970. The paper asserts 14 of the 17 were remarkably accurate, with only three having predicted too much warming.

One of the paper’s key assertions is that global emissions have risen more slowly than commonly forecast, which the authors claim explains why temperatures are running colder than the models predicted. The authors compensate for this by adjusting the predicted model temperatures downward to reflect fewer-than-expected emissions. Yet fewer-than-expected greenhouse gas emissions undercut the climate crisis narrative.

The U.N. Intergovernmental Panel on Climate Change has already reduced its initial projection of 0.3 degrees Celsius of warming per decade to merely 0.2 degrees Celsius per decade. Keeping in mind that skeptics have typically predicted approximately 0.1 degree Celsius of warming per decade, the United Nations has conceded skeptics have been at least as close to the truth with their projections as the United Nations. Moreover, global temperatures are likely only rising at a pace of 0.13 degrees Celsius per decade, which is even closer to skeptic predictions.

Even after the authors adjusted the model predictions to reflect fewer-than-expected greenhouse gas emissions, there remains at least one very important problem, which immediately jumped out at us when carefully examining the paper’s findings: The paper’s assertion of remarkable model accuracy rests on a substantial temperature spike from 2015 through 2017. A strong, temporary El Niño caused the short-term spike in global temperatures from 2015 to 2017. The plotted temperature data in the paper, however, show that temperatures prior to the El Niño spike ran consistently colder than the models’ adjusted predicted temperatures. When the El Niño recedes, as they always do, temperatures will almost certainly resume running colder than the models predicted, even after adjusting for fewer-than-expected greenhouse gas emissions.

Another problem with the paper is that it utilizes controversial and dubiously adjusted temperature datasets rather than more reliable ones. The paper relies on temperature datasets that are not replicated in any real-world temperature measurements. Surface temperature measurements and measurements taken by highly precise satellite instruments show significantly less warming than the authors claim. The authors rely on temperature datasets that utilize controversial adjustments to claim more recent warming than what has actually been measured, which further undercuts their claim of remarkable model accuracy.

Contrary to what has been written in many breathless media reports, the most important takeaways from the paper are that greenhouse gas emissions are rising at a more modest pace than predicted, the modest pace of global temperature rise reflects the modest pace of rising emissions, and climate models have consistently predicted too much warming—even after accounting for fewer-than-expected greenhouse gas emissions. A temporary spike in global temperatures reflecting the recent El Niño does not save the models from their consistent inaccuracy.

Climate change and bushfires — More rain, the same droughts, no trend, no science

by JoNova, December 24, 2019


To Recap: In order to make really Bad Fires we need the big three: Fuel, oxygen, spark.Obviously getting rid of air and lightning is beyond the budget. The only one we can control is fuel. No fuel = no fire.   Big fuel = Fireball apocalypse that we can;t stop even with help from Canada, California, and New Zealand.

The most important weather factor is rain, not an extra 1 degree of warmth. To turn the nation into a proper fireball, we “need” a good drought.  A lack of rain is a triple whammy — it dries out the ground and the fuel — and it makes the weather hotter too. Dry years are hot years in Australia, wet years are cool years. It’s just evaporative cooling for the whole country. The sun has to dry out the soil before it can heat up the air above it.  Simple yes?  El Nino’s mean less rain (in Australia), that’s why they also mean “hot weather”.

So ask a climate scientist the right questions and you’ll find out what the ABC won’t say: That global warming means more rain, not less. Droughts haven’t got worse, and climate models are really, terribly, awfully pathetically bad at predicting rain.

Four reasons carbon emissions are irrelevant

1. Droughts are the same as they ever were.

In the 178 year record, there is no trend. All that CO2 has made no difference at all to the incidence of Australian droughts. Climate scientists have shown droughts have not increased in Australia. Click the link to see Melbourne and Adelaide. Same thing.

3 degrees C?

by J. Curry, December 23, 2019 in ClimateEtc.


Is 3 C warming over the 21st century now the ‘best estimate’?  A reframing of how we think about climate change over the 21st century, and my arguments for 1 C.

There has been much discussion over on twitter of the new article by David Wallace-Wells:  We’re Getting a Clearer Picture of the Climate Future — and It’s n Not as Bad as it Once Looked.  ‘This article is interesting for several reasons, especially since Wallace-Wells has been ‘alarmist in chief.’

Simply put, it is now becoming more widely accepted that RCP8.5 concentration/emissions scenario is highly implausible.  See my previous post:

Who Is Winning The Climate Wars? (Part Two)

by F. Menton, December 18, 2019 in ClimateChangeDispatch


A few weeks ago (November 22), in a post titled “Who Is Winning The Climate Wars?”, I undertook to begin documenting the ever-growing chasm between the unhinged rhetoric of climate campaigners and the reality out there in the world.

Let’s collect a few data points over the past several weeks.

You probably know that the UN held its annual big climate conference this year in Madrid during the first two weeks of December.

That event provided the occasion for many campaigners to ramp up the volume of their claims, trying once again to stampede government representatives into agreeing to impoverish their people.

A few examples:

The fact is that outside of some wildly guilty European countries and the loons in the U.S. Democratic Party’s far Left, fewer and fewer people pay any attention whatsoever to the absurd climate apocalypse rhetoric.

Why Apocalyptic Claims About Climate Change Are Wrong

by P. Homewood, November 29, 2019 in NotaLotoPeopleKnowThat


Journalists and activists alike have an obligation to describe environmental problems honestly and accurately, even if they fear doing so will reduce their news value or salience with the public. There is good evidence that the catastrophist framing of climate change is self-defeating because it alienates and polarizes many people. And exaggerating climate change risks distracting us from other important issues including ones we might have more near-term control over.

I feel the need to say this up-front because I want the issues I’m about to raise to be taken seriously and not dismissed by those who label as “climate deniers” or “climate delayers” anyone who pushes back against exaggeration.

With that out of the way, let’s look whether the science supports what’s being said.

 

See also: Michael Shellenberger: Apocalypse Cancelled?

Half of 21st Century Warming Due to El Nino

by Roy Spencer, May 13, 2019 in GlobalWarming


A major uncertainty in figuring out how much of recent warming has been human-caused is knowing how much nature has caused. The IPCC is quite sure that nature is responsible for less than half of the warming since the mid-1900s, but politicians, activists, and various green energy pundits go even further, behaving as if warming is 100% human-caused.

The fact is we really don’t understand the causes of natural climate change on the time scale of an individual lifetime, although theories abound. For example, there is plenty of evidence that the Little Ice Age was real, and so some of the warming over the last 150 years (especially prior to 1940) was natural — but how much?

The answer makes as huge difference to energy policy. If global warming is only 50% as large as is predicted by the IPCC (which would make it only 20% of the problem portrayed by the media and politicians), then the immense cost of renewable energy can be avoided until we have new cost-competitive energy technologies.

The recently published paper Recent Global Warming as Confirmed by AIRSused 15 years of infrared satellite data to obtain a rather strong global surface warming trend of +0.24 C/decade. Objections have been made to that study by me (e.g. here) and others, not the least of which is the fact that the 2003-2017 period addressed had a record warm El Nino near the end (2015-16), which means the computed warming trend over that period is not entirely human-caused warming.

If we look at the warming over the 19-year period 2000-2018, we see the record El Nino event during 2015-16 (all monthly anomalies are relative to the 2001-2017 average seasonal cycle):

 

Renowned German Geologist Shocks Audience: “Climate Change Totally Exaggerated”…”Warming Least Of Our Problems” By P Gosselin on 12. Oct

par P. Gosselin, October 12, 2019 in NoTricksZone


It’s unusual to see rationality over climate change in the German media, but sometimes it manages to get through.

In April this year I missed an important podcast interview with one of the world’s most prominent Sahara Desert researchers, geologist Dr. Stefan Kröpelin, by the Düsseldorf-based German daily, Rheinische Post.

Image: University of Cologne

The two RP hosts conducting the interview seemed to expect Dr. Kröpelin would tell the audience how dire the consequences of man-made global warming are on the Sahara Desert and planet overall.

They didn’t get what they bargained for.

Warming does not lead to desertification

Instead, in the interview, Dr. Kröpelin rejected in very clear terms man’s major climatic impact and that global warming is only negative.

Kröpelin told listeners that history is very clear: When the globe is cold, the deserts expand. And when the globe is warm, deserts become greener and far more fruitful.

Kröpelin is a leading expert

Kröpelin has been studying the Sahara for over 40 years, spending weeks and months each year on site gathering data a reconstructing past climates. Naturedescribed Kröpelin as “one of the most devoted Sahara explorers of our time.”

At about 9 minutes into the interview, he explains how the Sahara was massive in size during the last glacial period, and that about ten thousand years ago it greened up once temperatures shot up early in the Holocene.

When asked (10:15) if he worries that things in the Sahara “will get much worse” due to climate change, Kröpelin tells the host and audience: “First, that is a statement I 100% reject”, adding that localized desertification has more to do with the population growth at the edges of the desert and that the people who live there are cutting down trees and extracting water from the ground.

Rising precipitation, shrinking desert

Has global warming stopped? The tap of incoming energy cannot be turned off

by Institute of Atmospheric Physics, Chinese Academy of Sciences, October 10, 2019 in WUWT


As a result of industrialization, the carbon dioxide in the Earth’s atmosphere has increased continuously over the past 100 years, which is considered as the main reason behind global warming. However, the observational global mean atmospheric temperature leveled off over the first decade of the 21st century, in contrast to the rapid warming during the late 20th century. This phenomenon, known as the “atmospheric warming slowdown” or “global warming hiatus”, has attracted great attention worldwide owing to its ostensible contradiction of the human-induced global warming theory.

The changes in ocean heat content might have a tight relationship with the atmospheric warming slowdown. Dr Changyu Li, Prof. Jianping Huang and their colleagues, a group of researchers from the Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, have had their findings published in Advances of Atmospheric Sciences.

In their paper, they explore the energy redistribution between the atmosphere and ocean at different latitudes and depths by using observational data as well as simulations of a coupled atmosphere-ocean box model.

Why Haven’t the Tropics Warmed Much? A Tantalizing Piece of Evidence

by Dr. Roy Spencer, Sep. 28, 2019 in WUWT


The radiative resistance to global temperature change is what limits the temperature change in response to radiative forcing from (say) increasing CO2, or the sun suddenly deciding to pump out a 1 percent more sunlight.

If the climate system sheds only a little extra energy with warming, it warms even more until radiative energy balance is restored. If it sheds a lot of energy, then very little warming is required to restore global energy balance. This is the climate sensitivity holy grail, and it will determine just how much warming results from increasing CO2 in the atmosphere.

John Christy and I are preparing a paper based upon Dept. of Energy-sponsored research explaining why the tropical troposphere hasn’t warmed as much in nature as in climate models. (The discrepancy exists for surface temperature trends; for both RSS and UAH tropical tropospheric trends; as well as for global reanalysis datasets). Danny Braswell and I did a lot of research on this subject about 5-10 years ago, and published several papers.

Without going into the gory details of why it is so difficult to measure “feedbacks” (how strong the climate system radiatively resists a temperature change in response to radiative forcing), I’m going to present one graph of new results from our work that suggests where the problem with the models might be.

‘Alarmism Enforcement’ On Hurricanes And Global Warming

by J. Curry, Sep; 9, 2019 in ClimateChangeDispatch


I used to be concerned about ‘consensus enforcement’ on the topic of climate change.  Now I am concerned about ‘alarmism enforcement.’

Ever since Hurricane Katrina in 2005, any hurricane causing catastrophic damage has been seized upon by climate alarmists as evidence of the horrors of global warming.

As if the record-holding hurricanes from the 1920s through the 1950s never happened.

The catastrophic damage to the Bahamas from Hurricane Dorian is no different.  The ‘official’ statement from the alarmist contingent of climate scientists appears to be this article in the Guardian, by Mann and Dessler:

Unfortunately for the alarmists, there are several factors that are getting in the way of the public promotion of the Mann/Dessler narrative:

Alabama-gate:  President Trump’s insistence on defending his erroneous statements about the forecasts for Dorian impacting Alabama.  A good article summarizing all this was co-authored by one of my former students at Georgia Tech, Brandon Miller [link].

After the Alabama National Weather Service office made a statement that Alabama was not at risk from Dorian, NOAA issued a statement defending President Trump  [link].

A WaPo article describes this latest development [link], and the subsequent outrage among scientists and NOAA employees (past and present.

This whole situation is taking the oxygen out of the room in terms of discussions regarding Dorian and global warming.  Gotta wonder if this was the strategy?

Does NASA’s Latest Figures Confirm Global Warming?

by Anthony Watts, May 9, 2019 in ClimateChangeDispatch


That’s an indication of the personal bias of co-author Schmidt, who in the past has repeatedly maligned the UAH dataset and its authors because their findings didn’t agree with his own GISTEMP dataset.

In fact, Schmidt’s bias was so strong that when invited to appear on national television to discuss warming trends, in a fit of spite, he refused to appear at the same time as the co-author of the UAH dataset, Dr. Roy Spencer.

A breakdown of several climate datasets, appearing below in degrees centigrade per decade, indicates there are significant discrepancies in estimated climate trends:

  • AIRS: +0.24 (from the 2019 Susskind et al. study)
  • GISTEMP: +0.22
  • ECMWF: +0.20
  • RSS LT: +0.20
  • Cowtan & Way: +0.19
  • UAH LT: +0.18
  • HadCRUT4: +0.17

Which climate dataset is the right one? Interestingly, the HadCRUT4 dataset, which is managed by a team in the United Kingdom, uses most of the same data GISTEMP uses from the National Oceanic and Atmospheric Administration’s Global Historical Climate Network.

Early 20th century global warming

by Judith Curry, January 25, 2019 in ClimateEtc.


A careful look at the early 20th century global warming, which is almost as large as the warming since 1950.  Until we can explain the early 20th century warming, I have little confidence IPCC and NCA4 attribution statements regarding the cause of the recent warming.

This is an issue that has long interested me.  Peter Webster wrote a previous post Mid 20th Century Global(?) Warming, which focused on the warm bump that culminated in the 1940’s.  My interest in this period was reignited while working on my report Sea Level and Climate Change.  Then, the recent paper by Zanna et al. discussed in Ocean Heat Content  Surprises further made the wheels turn.

In response to the Ocean Heat Content thread, David Appell posted a link to this paper on twitter:

The early 20th century warming: Anomalies, causes and consequences