Greenhouse 2011 – notsolive blogging3
More sessions on day 2. Tom Knutson from the US on tropical storms, Penny Whetton CSIRO on Australia’s climate projections, Ben Preston ex CSIRO and now Oak Ridge in the US on adaptation and Graeme Pearman on headology and energy futures.
Tom Knutson GFDL – tropical cyclones and hurricanes. Which projections of future tropical storm activity are most reliable? By looking at historical climate and hurricanes does that inform the future? Adjusting historical landfall in the US for observation density, gives no discernible trend. For the southern hemisphere, there is no trend in the Pacific and a small positive trend in the Indian Ocean, but there are data issues. The satellite data since 1981 shows rising trend but the record is brief. Longer term records also indicate that historical variability is larger than the recent trend in any case. Conclusion – no discernible influence but absence of evidence is not evidence of absence.
Model hindcasts simulating past hurricanes in the Atlantic are pretty good and these are being used for projections. The model only gets to Cat2, so it needs to be downscaled in another model. The result, published in Science (Bender et al., 2010) is 30% fewer storms for an 18 model average, but giving a doubling of Cat 4 and 5 storms by 2100. This would lead to an increase in the net damage potential of 28% by century’s end. Conclusion the increase in intensity outweighs the decrease in numbers.
The same model that was run for the Atlantic is now being run in the South West Pacific. It reproduces ENSO distributions (La Niña near Queensland coast, El Niño further east) but work is in progress. Models in the Australian region have less skill than the Atlantic for hindcasts. They project a decrease over time. Globally, the model consensus is for decrease but for individual basins, both increases and decreases are projected. For intensity, global increases are projected, but there are a few basins where decreases occur. Directions of change at the global level (frequency, intensity (winds) and rainfall) are said to be likely. The main differences between different models are probably due to different sea surface temperature patterns.
Penny Whetton CSIRO – National climate change projections, past present and future. Australian scenarios commenced with the Greenhouse 1987 conference. Subsequent products were 1990, 1992, 1996, 2001 and 2007. The last was a 130 page technical document and web-based products. Uncertainty has always been explicitly represented. These types of output are most useful for general purposes and scoping risks. More specific outputs need to be tailored towards particular uses.
The next set of projections is coming out in 2014 and will include the most recent emission representative concentration pathways being produced by the scientific community for the IPCC Fifth Assessment Report. One possibility for communication is to follow an approach used by the Dutch where four characteristic scenarios are chosen and more detailed scenarios can fit under those. For example, warm and drier, warm and slightly wetter, dry and hot. Finally a classification based on changing sea surface temps centred on the Indian and Pacific Oceans is being considered because it produces about 60% of the projected range of change over Australia.
Ben Preston Oak Ridge National Labs – adaptation was originally tagged as either being ‘lazy’ policy or go for it and develop, then adapt when we’re all rich in a changing climate. It has more recently evolved into a difficult issue to encompass. Adaptation is only one of a number of global issues of concern, and is embedded in the understanding of complex social-ecological processes. The issue can be divided into biophysical, socio-economic and institutional areas. Biophysical is related to extreme events and hazards but getting from the event to hazard is not simple. With socio-economic areas, human-driven changes are important; e.g. land use can either exacerbate or dampen climate extremes. Socially-driven vulnerability is also relevant – how future populations may be susceptible to existing risks/future risks. Changing adaptive capacity and also exposure to risks.
Institutional complexity – climate variability and change are revealing weaknesses in our institutions; e.g., MDB water policy and drought, Katrina. We see reform of existing institutions and a whole range of demands on institutions to consider climate risk. Adaptation isn’t just a local issue, but requires a multi-scaled approach at the governance and institutional scale.
Graeme Pearman consultant and adjunct Monash Uni – energy futures in a carbon constrained world. Graeme starts his exploration of climate risk in the human values embedded in our views of the world, aspirations and futures. What does it cost now and how will that change over time? The importance of energy in our way of life presents a fundamental problem for the believability of climate science and also policy. The main point is that better science will not be the breakthrough in this debate, the solution lies in addressing peoples’ core values. He addresses the issue from a central planning point of view rather than market oriented, e.g., from the governance issue where energy has to be provided under the social contract within which government operates.
Tech futures . Technology goes through a non-linear learning curve then reaches a period where costs go linear as market share is reached. This suggest fundamental limits to technology take-up (I don’t buy this – the argument works for many but not breakthrough tech that transforms). An analysis from Santos suggests that if all coal is replaced by gas by 2030 then emissions are 80% of 1990 levels. So a company-wide scenario is different to a community-wide scenario that may look to deeper targest. Holistic multi-targeted solutions to import dependence on liquid fuels will have no truck in Canberra or with government. However, McKinsey and ClimateWorks type approaches where the cheapest options are undertaken first are glass half full because there are many options for cost effective measures. This disjunct between the bleaker and more optimistic outlooks were not resolved in his talk, and remain as a wicked problem.