Monday, 10 September 2012

BACC II results presented and discussed in Tallinn

About 110 participants were at the BACC II Conference in Tallinn, Estonia, on 6 and 7 September. The scope of this short conference was to provide the scientific and stakeholder communities with summaries of the draft chapters for the BACC II book, which is expected to be published in late 2013.

The organizing team would like to thank the presenters for summarizing the chapters in such a good and comprehensive way. Thanks also to everybody who contributed to the vivid discussions and contributed with valuable comments to the chapter contents. They shall be taken up by authors to improve the chapters.

To give a short synopsis of the first day, it seems that BACC I results are confirmed and substantiated by the new information. Additional material allows to go into more detail in some issues, and some contested issues can be reconciled (e.g. sea surface temperature trends). For regional climate models (RCMs) it was evident that the ability to run multi-model ensembles seems a major addition, but clearly RCMs need further development. Homogeneity of data is till a problem and not taken seriously enough in some scientific quarters.

The question of attribution of the regional climate change signal to different drivers is a major new aspect of the BACC II book. Current knowledge reveals that attribution on the regional scale is still weak. The issue of multiple drivers on ecosystem and socio-economy changes is recognized, but more research efforts are clearly needed. Climate change is seen as a serious issue, but in many cases it remains questionable if it is a dominant issue.

On the second day, BACC chairman Hans von Storch summarized the presentations of the first day. The presentation can be downloaded here, and we would like to invite you to comment and discuss to here on this blog. A comprehensive summary can be viewed here. Maria Laamanen of the HELCOM Secretariat gave an overview over the work of HELCOM and the Baltic Sea Action Plan. HELCOM will use part of the BACC II material for a HELCOM Thematic Assessment in 2013. This collaboration between the scientific initiative of BACC and the scientific-political stakeholder HELCOM had been successful already for BACC I (2007-2008), from which also a HELCOM Thematic Assessment was published.

Last but not least, we would like to thank the moderator and discussion panelists (see programme) on the second day. The panel discussion demonstrated that there is still room for improving the interface between the science on the one hand, and decision makers, other stakeholders and the public on the other hand. The establishment of regional climate services could be a way to do this, a place where professionals from both sides work closely together to identify specific information needs, so that the best available scientific information can effectively be used. The role of the scientists themselves in propagating climate change messages was discussed controversely. While some panel speakers argued in favour of a stronger role of scientists in propagating climate change issues in public, this was clearly rejected by BACC Chairman Hans von Storch. He is convinced that it is crucial to keep a clear division between the science on the one hand, which is solely responsible for the scientific truth (with no compromises towards propagating a “good cause”), and other groups (like HELCOM, NGO´s etc), which have a different task in soceity, e.g. working towards an improved awareness for climate change issues in society. “Good” and “bad” are no categories in science. Society must decide whether e.g. a higer temperature and more rain is “good” or “bad”, this is not a scientific task.

For more information BACC II, see


Hans von Storch said...

Even if "scientific truth" is a difficult concept. ...
I enjoyed the meeting quite a bit; the BACC community, i.e., WE, have have matured in our debate and effort of determining consensus, also if that means consensus on disensus.

Mikko Alestalo said...

Thank you very much for the great effort to everybody concerned.

Some comments of mine to "BACC II results presented and discussed in Tallinn":

Regarding the public role of the scientists, it is of utmost importance that they take part in the communication of scientific results to the public. It is their responsibility to open the scientific results, together with the obvious risks involved to the mankind, in plain language. This cannot be left to non-specialists only. The minimum level of participation required is observed when obvious disinformation about the science is being distributed in the media, either by the good ones or the bad ones. The decision making will be left to the responsible politicians, but based on scientifically correct facts made understandable.

Mikko Alestalo said...

Some comments about the summary from BACC II conference by Hans von Storch (as requested):

Overall Summary
The sentence "...remains questionable if it is a dominant issue" is more like an opinion. What the other issues might be, noting that this is an assessment of climate change. Is there a scientific comparison of the various issues?

The summary rather highlights the problems. Some new scientific achievements of substance- which three are plenty - would be good to show as well.

In "Past climate variability", section 2.3:
It would be advantageous to show the various forcings in same units, e.g. in W/m2 for proper comparison. Aerosol forcing is not shown.

In Ch 4, "Impacts"
Instead of saying "very few evidence for impacts of CC as such!", one could say that due to the non-linearity of interacting processes the impact of CC is hard to isolate as such.

In "Detection and atribution" the last sentence in bold "The finding that present..." requires further consideration. There should be no uncertainty of the claim at the global level. The varying regional characteristics may be true, e.g. for aerosol forcing in Europe. Whether "serious limitation in knowledge" is true remains yet open.

Marcus Reckermann said...

I have now added a comprehensive summary by Anders.

Hans von Storch said...

Dear Mikko Alestalo,

let me first comment on the issue of "public role of the scientists, it is of utmost importance that they take part in the communication of scientific results to the public". I would fully agree.

They take part in informing the policymaking process, including the public debate, about the available knowledge, the uncertainty (part of the contemporary knowledge), but not in an attempt to push for a specific policy. Broadening the range of options to allow the democratic process to run its course, and not - as we often see - limiting the range to one preferred option). However, we see these attempts quite often, which means to use the "authority of science" for personal, value-driven agendas. This is a not a sustainable approach - many forget that the quality "sustainable" applies for all social activities, including science.

More on the other issues later.


Anonymous said...

The meeting was very stimulating.
Of major concern for the Baltic Sea marine system is the salinity and thus the water balance. It seems as most scenarios indicate a wetter north but a dryer south. Maybe we can state that this is a robust finding? It will have large impacts on the biogeochemistry of the Baltic Sea as the drainage basin in north and south are very different. The question if the net precipitation and river runoff to the Baltic Sea will increase or decrease is much more unclear. Historical evidence illustrates that a warmer climate is a dryer climate and a colder climate is a wetter climate in the region. Added to this aspect is that the climate models have large bias in the water balance components and they poorly model for example tree dynamics with regard to water uptake etc. I think we should not state that the Baltic Sea will be fresher or saltier but instead state that Baltic Sea may become fresher or saltier depending on the net inflow of freshwater to the Baltic Sea and more work is needed in salinity and water balance studies

Anders Omstedt said...

The comment above was mailed from and not planned to be anonymous

Best regards

Anders Omstedt