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Texto de referencia

1. IPCC Working Group I (2013) – 5th Assessment Report The Physical Science Basis – Summary for Policymakers – Intergovernmental Panel on Climate Change – http://www.climatechange2013.org/images/report/WG1AR5_SPM_FINAL.pdf
   “Projections in this Summary for Policymakers are for the end of the 21st century (2081–2100) given relative to 1986–2005, unless otherwise stated. To place such projections in historical context, it is necessary to consider observed changes between different periods. Based on the longest global surface temperature dataset available, the observed change between the average of the period 1850–1900 and of the AR5 reference period is 0.61 [0.55 to 0.67] °C.”
2. James Hansen and Makiko Sato (2016) – Regional Climate Change and National Responsibilities – Environmental Research Letters 11:034009 doi:10.1088/1748-9326/11/3/034009 – Climate Science, Awareness and Solutions, Columbia University Earth Institute – http://iopscience.iop.org/article/10.1088/1748-9326/11/3/034009/pdf
   “Thus 2°C warming relative to pre-industrial (1.7°C relative to 1951-1980) will result in bell curve shifts and climate impacts about three times greater than those that have occurred already. ”
3. Michael E. Mann – How Close Are We to ‘Dangerous’ Planetary Warming? – The Huffington Post Green, 12/03/2016 – http://www.huffingtonpost.com/michael-e-mann/how-close-are-we-to-dangerous-planetary-warming_b_8841534.html
   “It is evident that roughly 0.3C greenhouse warming had already taken place by 1900, and roughly 0.2C warming by 1870. While that might seem like a minor amount of warming, it has significant implications for the challenge we face in stabilizing warming below 2C, let alone 1.5C, as we shall see below.”
4. P. Schurer et al (2013) – Separating Forced from Chaotic Climate Variability over the Past Millennium – Journal of Climate 26:6954-6973 doi:10.1175/JCLI-D-12-00826.1 – School of GeoSciences, The University of Edinburgh – http://www.geos.ed.ac.uk/homes/ghegerl/Schureretal_JCli.pdf – 5 autores
   “Reconstructions of past climate show notable temperature variability over the past millennium … External forcing is found to contribute significantly to long-term temperature variations irrespective of the proxy reconstruction, particularly from 1400 onward … for the first time a significant contribution from greenhouse gas variations to the cold conditions during 1600–1800 is also detected. The proxy reconstructions tend to show a smaller forced response than is simulated by the models. This discrepancy is shown, at least partly, to be likely associated with the difference in the response to large volcanic eruptions between reconstructions and model simulations.”
5. Thomas E. Bowman et al (2009) – Creating a Common Climate Language – Science 324:36-37 doi:10.1126/science.324.5923.36b – Climate Solutions Project Bowman Global Change Signal – http://www.meteo.psu.edu/holocene/public_html/shared/articles/BowmanetalLetterScience09.pdf – 5 autores
   “We urge scientists and science journal editors to create a single, readily understood frame of reference for two critical concepts in climate science … we strongly recommend referencing atmospheric concentrations of all long-lived greenhouse gases as CO2-equivalent (CO2e), not only CO2. CO2e is the concentration of CO2 that would cause the same level of radiative forcing as a given mixture of CO2 and other greenhouse gases. Moreover, because understanding total anthropogenic warming is important for assessing risk, we recommend referencing a standardized pre-industrial temperature baseline. Adopting these two references as elements of our common language will help reduce confusion that has been inadvertently caused by reporting results that appear to be similar.”
6. Ed Hawkins et al (2016) – Estimating pre-industrial global temperature – Geophysical Research Abstracts 18:EGU2016-3081 – European Geosciences Union, 19/04/2016 – NCAS-Climate, University of Reading – http://meetingorganizer.copernicus.org/EGU2016/EGU2016-3081.pdf – 11 autores
   “The United Nations Framework Convention on Climate Change (UNFCCC) process has recently agreed to try and limit global temperature rise to ‘well below 2◦C above pre-industrial levels’. But what period is ‘pre-industrial’? Remarkably, perhaps, this is not defined within the UNFCCC or its many agreements and protocols. Neither was the term used in the IPCC’s fifth assessment report (AR5) when discussing when particular temperature levels might be reached, due to the lack of a robust definition. Here, we discuss the important factors to consider when defining a period to call pre-industrial, based on estimates of historical radiative forcings and the availability of climate observations. There is no perfect period to choose, but we suggest that 1720-1800 is the optimal choice.”
7. James E. Hansen and Makiko Sato (2011) – Earth’s Climate History: Implications for Tomorrow – GISS NASA – NASA Goddard Institute for Space Studies + Columbia University Earth Institute – http://www.giss.nasa.gov/research/briefs/hansen_15/PaleoImplications.pdf
   “The paleoclimate record makes it clear that a target to keep human made global warming less than 2°C, as proposed in some international discussions, is not sufficient – it is a prescription for disaster … that inertia is not our friend – it means that we are building in changes for future generations that will be difficult, if not impossible, to avoid.”
8. Hanqin Tian et al (2016) – The terrestrial biosphere as a net source of greenhouse gases to the atmosphere – Nature 531:225–228 doi:10.1038/nature16946 – International Center for Climate and Global Change Research, School of Forestry and Wildlife Sciences, Auburn University – 23 autores
   “The future role of the biosphere as a source or sink of GHGs will depend on future land-use intensification pathways and on the evolution of the land CO2 sinks.”