CLIMATE CHANGE 2014 IPCC V Assessment Synthesis Report CAMBIO CLIMÁTICO V Evaluación del PANEL Changement Climatique le V ème Rapport

2014

IPCC Fifth Assessment (AR5) Synthesis Report

The following are excerpts from the abovementioned Synthesis Report, a communication still subjected to editing.

The purpose of this comment is to make our readers aware of some of the key findings by the scientists of the Intergovernmental Panel on Climate Change.

Once again we must thank the Cámara de Exportadores de la República Argentina for their making this valuable material available to us.

We will concentrate, as already mentioned, on some of their key contributions in order that you may have a first hand view of what the papers are writing about  these days.

Lo que sigue son extractos de la Quinta Evaluación del Panel Intergubernamental de Cambio Climático - Informe Resumen, una comunicación aún sujeta a edición. El propósito de este comentario es llamar la atención de nuestros lectores sobre algunas de las conclusiones clave de este panel de científicos de todo el mundo. Y una vez agradecemos a C.E.R.A. por acercarnos el material original, del cual hemos extraído aquello que nos pareció más relevante, y a la vez comprensible por aquellos que no somos científicos especializados en Cambio Climático.

Mauricio López Dardaine

Source: IPCC Fifth Assessment Synthesis Report

“The Synthesis Report (SYR) of the IPCC Fifth Assessment Report (AR5) provides an overview of the state of knowledge concerning the science of climate change, emphasizing new results since the publication of the IPCC Fourth Assessment Report in 2007 (AR4). The SYR synthesizes the main findings of the AR5 (IPCC) based on contributions from Working Group I (The Physical Science Basis), Working Group II (Impacts, Adaptation and Vulnerability), and Working Group III (Mitigation of Climate Change), plus two additional IPCC reports (Special Report on Renewable Energy and Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation).”

“Les émissions de gaz à effet  de serre d’origine humaine ont crû depuis l’ère pré-industrielle poussés en grande partie par la croissance économique et de population. Entre 2000 et 2010 les émissions ont été les plus grandes de l’histoire. Les émissions historiques ont porté les concentrations atmosphériques du dioxyde de carbone, de méthane et d’oxyde nitreux, à un niveau sans précédent au moins durant les 800.000 dernières années, ce qui a géneré une absortion [considerable] de la part du système climatique. »

“Anthropogenic greenhouse gas emissions have increased since the pre-industrial era driven largely by economic and population growth. From 2000 to 2010 emissions were the highest in history. Historical emissions have driven atmospheric concentrations of carbon dioxide, methane and nitrous oxide, to levels that are unprecedented in at least the last 800,000 years, leading to an uptake of energy by the climate system.”

"Las emisiones de gases de efecto invernadero de caracter antropogénico (de origen humano) han crecido desde la era pre-industrial impulsadas en gran medida por el crecimiento poblacional y económico. Entre 2000 y 2010 las emisiones han sido las mayores de la historia. Las emisiones históricas han llevado las concentraciones atmosféricas de dióxido de carbono, metano y óxido nitroso, a un nivel sin precedentes por lo menos en los últimos 800.000 años, lo que ha generado una absorción [considerable] por parte del sistema climático."  

“Observed changes in the climate system

Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, and sea level has risen.

El calentamiento del sistema climático es inequívoco, y desde
los años cincuenta (1950s), muchos de los cambios observado no tienen precedentes en siglos ni en milenios. La atmósfera terrestre y los océanos se han calentado, la cantidad de nieve y hielo ha disminuido, y el nivel del mar ha subido. 

Atmosphere

Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850. The period from 1983 to 2012 was very likely the warmest 30-year period of the last 800 years in the Northern Hemisphere, where such assessment is possible (high confidence) and likely the warmest 30-year period of the last 1400 years (medium confidence).

Cada una de las tres últimas décadas ha sido sucesivamente más caliente al nivel de la superficie de la Tierra que cualquier década precedente desde 1850. El período que va desde 1983 a 2012 ha sido muy probablemente el período de 30 años más caluroso de los últimos 800 años en el Hemisferio Norte, donde tal evaluación es posible (alto nivel de confianza) y probablemente el período de 30 años más caluroso  de los últimos 1400 años (nivel medio de confianza).

Ocean

Ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the energy accumulated between 1971 and 2010 (high confidence) with only about 1% stored in the atmosphere . On a global scale, the ocean warming is largest near the surface, and the upper 75 m warmed by 0.11 [0.09 to 0.13] °C per decade over the period 1971 to 2010. It is virtually certain that the upper ocean (0−700 m) warmed from 1971 to 2010, and it likely warmed between the 1870s and 1971. It is likely that the ocean warmed from 700 m to 2000 m from 1957 to 2009 and from 3000 m to the bottom for the period 1992 to 2005.

Energy accumulation within the Earth’s climate system

It is very likely that regions of high surface salinity, where evaporation dominates, have become more saline, while regions of low salinity, where precipitation dominates, have become fresher since the 1950s. These regional trends in ocean salinity provide indirect evidence for changes in evaporation and precipitation over the oceans and thus for changes in the global water cycle (medium confidence).

Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass (high confidence). Glaciers have continued to shrink almost worldwide (high confidence). Northern Hemisphere spring snow cover has continued to decrease in extent (high confidence). There is high confidence that there are strong regional differences in the trend in Antarctic sea ice extent, with a very likely increase in total extent.

Glaciers have lost mass and contributed to sea-level rise throughout the 20th century. The rate of ice mass loss from the Greenland ice sheet has very likely substantially increased over the period 1992 to 2011, resulting in a larger mass loss over 2002 to 2011 than over 1992 to 2011. The rate of ice mass loss from the Antarctic ice sheet, mainly from the northern Antarctic Peninsula and the Amundsen Sea sector of West Antarctica, is also likely larger over 2002 to 2011.

The annual mean Arctic sea ice extent decreased over the period 1979 (when satellite observations commenced) to 2012. The rate of decrease was very likely in the range 3.5 to 4.1% per decade. Arctic sea ice extent has decreased in every season and in every successive decade since 1979, with the most rapid decrease in decadal mean extent in summer (high confidence).

There is very high confidence that the extent of northern hemisphere snow cover has decreased since the mid 20th century by 1.6 [0.8 to 2.4]% per decade for March and April, and 11.7% per decade for June, over the 1967 to 2012 period. There is high confidence that permafrost temperatures have increased in most regions of the Northern Hemisphere since the early 1980s, with reductions in thickness and areal extent in some regions.

Sea level

Over the period 1901–2010, global mean sea level rose by 0.19 [0.17 to 0.21] m. The rate of sea-level rise since the mid-19th century has been larger than the mean rate during the previous two millennia (high confidence).

Rates of sea-level rise over broad regions can be several times larger or smaller than the global mean sea-level rise for periods of several decades, due to fluctuations in ocean circulation. Since 1993, the regional rates for the Western Pacific are up to three times larger than the global mean, while those for much of the Eastern Pacific are near zero or negative.”