Archives par mot-clé : Global Warming

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