Archives par mot-clé : Hiatus

Global temperature hiatus may not have ended after all, new study suggests

by D. Whitehouse, Sep 23, 2022 in NetZeroWatch


The so-called hiatus in global annual average temperature between 2002 – 2014, once controversial to some but now well-established in the peer-reviewed literature, ended in 2014 with the start of a series of record-breaking El Nino events that spiked global temperature with a subsequent fall-back. Now a new study into the effect of man-made aerosol pollution adds to likely reasons for the end of the hiatus, and may point to lower estimates for future global warming.

An international research team writing in the journal Atmospheric Chemistry and Physics, uses satellite data to show that concentrations of aerosol particles have decreased significantly since 2000. This is good news as cleaner air benefits health, but it also reduces particles’ which have a cooling effect on the terrestrial climate.

According to the Intergovernmental Panel on Climate Change (IPCC), by 2019 the global temperature had risen by 1.1 degrees Celsius compared to pre-industrial levels due to increasing greenhouse gasses from burning fossil fuels. At the same time the combustion of fossil fuels emit aerosols which cool our climate by reflecting sunlight and increasing the reflectivity of clouds.

Professor Johannes Quaas, a meteorologist at Leipzig University, and colleagues from Europe, China, and the US have published robust observational evidence of significant reduction of aerosol pollution and improved global air quality.

Global temperature hiatus may not have ended after all, new study suggests

by Dr D. Whitehouse, Sep 23, 2022 in NetZeroWatch


The so-called hiatus in global annual average temperature between 2002 – 2014, once controversial to some but now well-established in the peer-reviewed literature, ended in 2014 with the start of a series of record-breaking El Nino events that spiked global temperature with a subsequent fall-back. Now a new study into the effect of man-made aerosol pollution adds to likely reasons for the end of the hiatus, and may point to lower estimates for future global warming.

An international research team writing in the journal Atmospheric Chemistry and Physics, uses satellite data to show that concentrations of aerosol particles have decreased significantly since 2000. This is good news as cleaner air benefits health, but it also reduces particles’ which have a cooling effect on the terrestrial climate.

According to the Intergovernmental Panel on Climate Change (IPCC), by 2019 the global temperature had risen by 1.1 degrees Celsius compared to pre-industrial levels due to increasing greenhouse gasses from burning fossil fuels. At the same time the combustion of fossil fuels emit aerosols which cool our climate by reflecting sunlight and increasing the reflectivity of clouds.

Professor Johannes Quaas, a meteorologist at Leipzig University, and colleagues from Europe, China, and the US have published robust observational evidence of significant reduction of aerosol pollution and improved global air quality.

When taken together with a couple of super-strong El Nino events which temporarily drove up global temperature (see graph below), the new findings suggest that the global warming hiatus — clearly evident prior to 2014 — may not have ended yet. If NASA’s satellite data are confirmed, it would suggest that much of the very moderate changes in global temperature this century may have been driven primarily by cleaner air and naturally-occurring El Ninos.

Global temperature changes 2000-2022. Source: Met Office/HadCRUT5

New Study: 90 Papers Were Published On The ‘Hiatus’ From 2009-2019. Now They Say It Never Happened.

by K. Richard, Apr 18, 2022 in NoTricksZone


The claimed warming rate during the (1998-2001 to 2012-’13) “hiatus” ranged from -0.07°C to +0.17°C per decade.

In late 2012, the IPCC had an ongoing dilemma about what to do about the uncooperative global temperatures. The HadCRUT3 data set government bureaucrats had been using since the first report in 1990 actually showed the global mean surface temperatures had been declining since 1998. This was not going further the we-must-act-on-global-warming-now narrative, of course.

Enter Phil Jones, the global temperature data set overseer at East Anglia’s Climate Research Unit (CRUTEM). He’s the scientist who famously admitted that when the temperature data doesn’t exist, they are “mostly made up.”

 

Jones’s CRU and the Met Office (Hadley) then jointly constructed the newer HadCRUT4 version to help advance the narrative. This version changed the data just in time for the 5th IPCC assessment (AR5, 2013). The 1998-2001 temperatures  were allowed to stay the same, but an additional 0.1 to 0.2°C was tacked on to anomalies from 2002 onwards. The effect was to transform the 1998-2012 slight cooling in HadCRUT3 into a 0.04°C per decade−1 warming in HadCRUT4.

Image Source: woodfortrees.org 

 

The planet is no longer warming

by A. May-(Javier), February 6, 2019 in WUWT


According to the IPCC at least 77%, but more probably 120%, and up to 200% of the observed warming, has been caused by GHGs.

The rate of CO2 change (the atmospheric increase in CO2 every year) has been increasing almost linearly since 1959 and is currently ~2.4 ppm/year.

Figure 2. Mauna Loa rate of increase in CO2 (ppm/year). Thin line, 12-month increase. Thick line, gaussian smoothing. Red line, 2nd order polynomial least-squares fit to the yearly increase.