Le site Mashable nous informe qu'une nouvelle étude parue dans nature climate change confirme une accélération de la hausse du niveau des mers en grande partie due à la fonte de la calotte glaciaire du Groenland.
Voici l'abstract de l'étude :
- Global mean sea level (GMSL) has been rising at a faster rate during the satellite altimetry period(1993–2014) than previous decades, and is expected to accelerate further over the coming century1. However, the accelerations observed over century and longer periods2 have not been clearly detected in altimeter data spanning the past two decades3–5. Here we show that the rise, from the sum of all observed contributions to GMSL, increases from 2.2 ± 0.3 mm yr−1in 1993 to 3.3 ± 0.3 mm yr−1in 2014. This is in approximate agreement with observed increase in GMSL rise, 2.4 ± 0.2 mm yr−1(1993) to 2.9 ± 0.3 mm yr−1 (2014), from satellite observations that have been adjusted for small systematic drift, particularly affecting the first decade of satellite observations6. The mass contributions to GMSL increase from about 50% in 1993 to 70% in 2014 with the largest, and statistically significant, increase coming from the contribution from the Greenland ice sheet, which is less than 5% of the GMSL rate during 1993 but more than 25% during 2014. The suggested acceleration and improved closure of the sea-level budget highlights the importance and urgency of mitigating climate change and formulating coastal adaption plans to mitigate the impacts of ongoing sea-level rise.
- hausse du niveau des mers en 1993 : +2,2mm par an (±0,3)
- hausse du niveau des mers en 2014 : +3,3mm par an (±0,3)
- contribution de la fonte des glaces en 1993 : 50% (le reste expansion due à la chaleur des océans)
- contribution de la fonte des glaces en 2014 : 70%
- contribution du Groenland à la fonte des glaces en 1993 : 5% au plus
- contribution du Groenland à la fonte des glaces en 2014 : 25% et plus
- Temperature sounding microwave radiometers flown on polar-orbiting weather satellites provide a long-term, global-scale record of upper-atmosphere temperatures, beginning in late 1978 and continuing to the present. The focus of this paper is a lower-tropospheric temperature product constructed using measurements made by the Microwave Sounding Unit channel 2, and the Advanced Microwave Sounding Unit channel 5. The temperature weighting functions for these channels peak in the mid to upper troposphere. By using a weighted average of measurements made at different Earth incidence angles, the effective weighting function can be lowered so that it peaks in the lower troposphere. Previous versions of this dataset used general circulation model output to remove the effects of drifting local measurement time on the measured temperatures. In this paper, we present a method to optimize these adjustments using information from the satellite measurements themselves. The new method finds a global-mean land diurnal cycle that peaks later in the afternoon, leading to improved agreement between measurements made by co-orbiting satellites. The changes result in global-scale warming (global trend (70S-80N, 1979-2016) = 0.174 C/decade), ~30% larger than our previous version of the dataset (global trend, (70S-80N, 1979-2016) = 0.134C/decade). This change is primarily due to the changes in the adjustment for drifting local measurement time. The new dataset shows more warming than most similar datasets constructed from satellites or radiosonde data. However, comparisons with total column water vapor over the oceans suggest that the new dataset may not show enough warming in the tropics.
L'étude est de Carl Mears, qui travaille pour RSS, le "partenaire" (ou l'ennemi ?) de Roy Spencer et John Christy qui, eux, bossent pour UAH.
Il n'est pas anodin de remarquer que Carl Mears n'est pas climatosceptique...
Il n'en faut pas plus pour déchainer les furies complotistes en tout genre, par exemple sur CarbonBrief :
- the surface data were "adjusted" to eliminate the "pause", and the long knives came out against the satellite data, seeking to disparage it at every turn. Now, the RSS version of the satellite data has been "adjusted" to agree with the surface record. The UAH team will eventually retire, and it will all get swept down the memory hole. The plain fact of the matter is that the data are uncertain, and there are endless ways in which it can be "adjusted" to show greater or lesser warming. After all, we're talking "adjustments" here that are about 1/10th of a degree Celsius - a change that most people could not even detect. A normal person's own body temperature varies by about 12 times as much as this during a typical day (+/- about 0.6 C). The problem is that, with the surface data and now RSS, the focus is on ferreting out "adjustments" that show superficially greater warming. Little to no effort is made to justify "adjustments" that lead to greater cooling. It is an exercise in confirmation bias. The scientific method has become a casualty of agenda driven "science".Up until maybe 5 years ago, the surface data and the satellite data matched fairly well. Then,
The Daily Caller, Instapundit, PJ Media, The Hill, Bloomberg... vous avez dit biais de confirmation ?