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WMO: Greenhouse Gases Hit Record Level And Grew At Their Fastest Rate Since 1984 Last Year...

 

A surge in carbon dioxide (CO2) emissions drove the concentration of greenhouse gases in the atmosphere upwards at the fastest rate since 1984 last year reaching new record high levels, according to the World Meteorological Organization (WMO). The WMO Global Atmosphere Watch (GAW) coordinates observations of the most important contributors to climate change: long-lived greenhouse gases (LLGHG) including CO2, methane and nitrous oxide. In the figure above, their radiative forcing (RF) – or warming effect - is plotted along with a simple illustration of the impacts on future RF of different emission reduction scenarios. Analysis of GAW observations shows that a reduction in RF from its current level (2.92 Wm–2 in 2013) requires significant reductions in anthropogenic emissions of all major greenhouse gases (GHGs). Image courtesy:WMO. Full story here.

 

 

...As New Statistical Analysis Of Temperatures Dates Start Of The Global Warming Pause To 1995...

 

A statistical analysis of global temperature data indicates that the so called pause or hiatus in global warming dates back to 1995 – 19 years ago. The existence of the pause in global warming was acknowledged by the Intergovernmental Panel on Climate Change last year but there has been significant debate about the actual duration of this hiatus with some commentators alleging that the length is exaggerated by cherry-picking the start date as 1998 – a particularly warm year. Ross McKitrick from the Department of Economics at the University of Guelph in Canada believes his statistical analysis used in the paper published in the Open Journal of Statistics avoids the potential biases and is immune to the charge of cherry-picking. In the conclusion to the paper McKitrick, an acknowledged climate sceptic, writes: “In the surface data we compute a hiatus length of 19 years”. This graphic from the paper shows the trend in temperatures in the HadCRUT 4 data set and illustrates that a flat trend can be dated back to 1995. Trend magnitudes  are black dots and the 95% robust confidence intervals are solid lines. Image courtesy of OJS and Ross McKitrick. Full story here.

 

 

...While Researchers Suggest Cause Of Pause Due To Natural Variations Driven By The Pacific Ocean...

 

Natural variations linked to long term changes in the Pacific Ocean have played an important role in both the acceleration of global warming seen at the end of the 20th century and in the so called global warming pause that has continued since the late 1990s, according to research published in Nature Climate Change. The researchers suggest that these cycles accounted for 47 per cent of the observed temperature rise in the 1980s. This graphic from the paper shows observed and simulated change in global-mean surface temperature. Annual-mean time series relative to 1961–1990 mean derived from observations (black), ASYM-H (red) and ASYM-C (blue) experiments. Shading represents ranges of 95% confidence. Linear trends for 1961–2012 and 2003–2012 are denoted at the top. Time series from the combined CMIP3 and CMIP5 models is also shown by the grey curve, with shading representing one standard deviation. Red and blue vertical dashed lines show the occurrence of El Niño and La Niña events, respectively. Three major volcanic eruptions (Agung, El Chichón and Pinatubo) are indicated by green triangles. One implication of this research – not mentioned explicitly in the paper – is that global climate sensitivity to carbon dioxide levels may be at the lower end of the range of possibilities. Courtesy: authors and Nature Climate Change. Full story here.

 

 

...And Another Research Team Say Cause Of The Pause Is To Be Found In Atlantic Rather Than Pacific

 

New research pins the cause of the global warming pause on heat storage deep in the Oceans. But scientists conclude it is the Atlantic and Southern Oceans, and not the Pacific Ocean, that have absorbed the excess heat that would otherwise have fueled continued warming. The finding is a surprise, since the current theories had pointed to the Pacific Ocean as the culprit for hiding heat, say the researchers. This graphic is courtesy of researcher Ka-Kit Tung  of the University of Washington and it shows: (top) global average surface temperatures, where black dots are yearly averages - two flat periods (hiatus) are separated by rapid warming from 1976-1999; (middle) observations of heat content, compared to the average, in the north Atlantic Ocean; (bottom) salinity of the seawater in the same part of the Atlantic - higher salinity is seen to coincide with more ocean heat storage. Story here.