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Heaven belongs to us all – the new papal encyclical

Filed under: — stefan @ 18 June 2015

Guest post by Brigitte Knopf

With his encyclical “Laudato Si” the Pope has written more than a moral appeal without obligation. He has presented a pioneering political analysis with great explosive power, which will probably determine the public debate on climate change, poverty and inequality for years to come. Thus, the encyclical is also highly relevant to me as a non-Catholic and non-believer; the implications of the encyclical are very apparent through the eyes of a secular person.

The core of the encyclical makes clear that global warming is a “global problem with grave implications: environmental, social, economic, political and for the distribution of goods” (25 – where the numbers refer to the numbering in the encyclical). The reasons identified are mainly the current models of production and consumption (26). The encyclical emphasizes that the gravest effects of climate change and the increasing inequality are suffered by the poorest (48). Since we face a complex socio-ecological crisis, strategies for a solution demand an integrated approach to combating poverty (139). So far, however, governments have not found a solution for the over-exploitation of the global commons, such as atmosphere, oceans, and forests (169). Therefore, the encyclical focusses on actors, such as non-governmental organizations, cooperatives and intermediate groups (179) and calls for a dialogue between politics, science, business and religion.

The encyclical is, with 246 individual points, too extensive to be discussed in here in its entirety, but three aspects are particularly noteworthy:

  1. it is based unequivocally onthe scientific consensusthat global warmingis taking placeand that climate changeis man-made; itrejects thedenialof anthropogenicwarming;
  2. it unmasks the political and economic structures of power behind the climate change debate and stresses the importance of non-state actors in achieving change; and
  3. it defines the atmosphere and the environment as a common good rather than a “no man’s land”, available for anyone to pollute. This underlines that climate change is strongly related to the issues of justice and property rights.

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Debate in the noise

Last week there was an international media debate on climate data which appeared to be rather surreal to me. It was claimed that the global temperature data had so far shown a “hiatus” of global warming from 1998-2012, which was now suddenly gone after a data correction. So what happened?

One of the data centers that compile the data on global surface temperatures – NOAA – reported in the journal Science on an update of their data. Some artifacts due to changed measurement methods (especially for sea surface temperatures) were corrected and additional data of previously not included weather stations were added. All data centers are continually working to improve their database and they therefore occasionally present version updates of their global series (NASA data are currently at version 3, the British Hadley Centre data at version 4). There is nothing unusual about this, and the corrections are in the range of a few hundredths of a degree – see Figure 1. This really is just about fine details. More »

A hypothesis about the cold winter in eastern North America + Update

Filed under: — stefan @ 30 March 2015

The past winter was globally the warmest on record. At the same time it set a new cold record in the subpolar North Atlantic – and it was very cold in the eastern parts of North America. Are these things related?

Two weeks ago NOAA published the following map of temperature anomalies for the past December-January-February (i.e. the Northern Hemisphere winter). One week ago, we published a paper in Nature Climate Change (which had been in the works for a few years) arguing that the cold in the subpolar North Atlantic is indicative of an AMOC slowdown (as discussed in my last post). Immediately our readers started to ask (as we indeed had been asking ourselves): does the cold winter in eastern North America (culminating in the Inhofe snowball incident) have anything to do with what is going on in the Atlantic?

Winter15NOAAFig. 1 Temperature anomaly map for the past december-january-february, from NOAA.

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  1. S. Rahmstorf, J.E. Box, G. Feulner, M.E. Mann, A. Robinson, S. Rutherford, and E.J. Schaffernicht, "Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation", Nature Climate change, vol. 5, pp. 475-480, 2015.

What’s going on in the North Atlantic?

Filed under: — stefan @ 23 March 2015

The North Atlantic between Newfoundland and Ireland is practically the only region of the world that has defied global warming and even cooled. Last winter there even was the coldest on record – while globally it was the hottest on record. Our recent study (Rahmstorf et al. 2015) attributes this to a weakening of the Gulf Stream System, which is apparently unique in the last thousand years.

The whole world is warming. The whole world? No! A region in the subpolar Atlantic has cooled over the past century – unique in the world for an area with reasonable data coverage (Fig. 1). So what’s so special about this region between Newfoundland and Ireland?


Fig. 1 Linear temperature trend from 1900 to 2013. The cooling in the subpolar North Atlantic is remarkable and well documented by numerous measurements – unlike the cold spot in central Africa, which on closer inspection apparently is an artifact of incomplete and inhomogeneous weather station data.

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Severe Tropical Cyclone Pam and Climate Change

Filed under: — stefan @ 18 March 2015

Guest post by Kerry Emanuel

In the past 16 months, two exceptionally intense tropical cyclones, Haiyan and Pam, have struck the western Pacific with devastating effect. Haiyan may have had the highest wind speeds of any tropical cyclone on record, but we will never know for sure because we do a poor job estimating the intensity of storms that are not surveyed by aircraft. (Currently, only North Atlantic tropical cyclones are routinely reconnoitered by aircraft, and only if they threaten populated regions within a few days.) Pam’s analyzed intensity puts it within 10 knots of the most intense storms on record in the South Pacific, but here again this is within the error bars of satellite-derived intensity estimates.

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