Yes, the world is warming, on average, but what kills is not the average temperature rising by one or two degrees, its drought,
extreme events such as storms, ocean acidification, etc. The danger is that people think we're heading for a Mediterranean climate here in N Europe, etc. and that global warming might not be a bad thing for chilly Ireland, for example, when massive droughts and crop failures (across Europe and elsewhere) are starting to threaten global food supplies.
Any evidence that those are happening on a more frequently scale than usual? I hear the usual fears and I see the usual lack of evidence. Confirmation bias is an ever present threat under these circumstances.
Yes, but it is and will be probabilistic. See for example this on the Moscow heat waves, for example, and the discussions at RealClimate. Attribution studies are very expensive (in time and money, for computing ensembles), but are a key body of work over the last few years, and there is a section of the upcoming IPCC AR5 report summarizing it. The IPCC reports are
the best summary of the science, even though they are very conservative.
And the term, anthropogenic climate change mixes a number of human activities. Sure, AGW, desertification, and deforestation (to name three problems with likely global impact which would fall under the umbrella term above) have synergistic effects. But lumping them all under one category as you do here, doesn't help us figure out which activities are causing which problems or how to use our limited resources best to mitigate the effects of what we're doing.
Yes, and I didn't go into details. I didn't mention desertification or deforestation, for example, but you're right about synergistic effects. For example I've been working providing data to a group at NUI Maynooth" studying the effects on forests: the (measured and predicted) lengthing growing season leads to multiple generations of tree-predating insects surviving. Some species may have difficulty surviving this, so foresters need to know 30 years in advance what species to plant.
In particular, bad policy has been a remarkable driver of higher costs and fairly often confused for an AGW-related harm. For example just from the US, food prices have been driven up by ethanol subsidies for corn (which simultaneously drives up the price of corn, the price of gas, and reduces the availability of food) and the total cost of damage from cyclonic weather and flooding has been driven up by US government flood insurance policy (which still subsidizes to some degree construction in flood-prone areas).
Yes. The numbers I've seen say that the shortfall in wheat due to the Russian heatwave in 2010 equalled the crop production in Europe diverted to make ethanol under EU policy for 5% ethanol mix, for example.
Its ironic that the denialists
Yet another anti-scientific propaganda term. I find it a bit hypocritical to complain about the scientific basis of criticism of AGW while simultaneously using language that discourages scientific thought.The problem here is that there is a wide range of criticism of AGW from simply claiming it doesn't exist to disputing the claims of harm from global warming. I agree that some degree of anthropogenic global warming is occurring (though the basis for such a claim is much shakier than proponents are willing to admit), but I don't agree that the harm from AGW is as great as claimed.
Non-scientific, yes. The terms "sceptic", "denialist","AGW believer",etc are not pro- or anti-scientific, they're political.
And I will not shy from the politics. There are simply no proper sceptics left in the field. Ten, twenty years ago sceptics had some valid questions that needed answering: discrepancies in satellite records, ocean heat, Lindzens "cloud halo" theories, for example. But over the last decade or so, they've all been answered, with the best sceptics coming up with new evidence or results (eg. this), or quietly leaving the field. The remainder are simply denialists: unmoved and simply repeating the same disproved lines, not attempting to answer the questions scientifically but simply stall political changes they don't want.
For example, I have yet to see evidence that greenhouse gas emissions causes loss of crop yield globally within two orders of magnitude of bad farming practices.
Yes. For ACC vs bad farming practices, I'll leave that to ag. scientists, but here in Ireland for example we've seen a bad year, with yields down 20% or so (preliminary) due to bad weather: heavy rainfall. Now we've seen an increase in the rainfall similar to that predicted by our climate models (though not in details: we see a step-change in the rainfall in the 1970s for example I don't think the models have reproduced, but we have not enough climate/ocean measurements from that time to properly initalize the models, so I don't think we'll ever simulate the climate of the 1950s-1990s to within measurement error).
Could we scientifically attribute the rainfall this year to ACC? we could run a large ensemble model (such as the UK Met office did for Russia, 2010) but it would be exteremely expensive in computational time and scientist time, and would still lead a probabilistic result that denialists would dismiss. The preference instead is to concentrate our efforts on developing seasonal forecasting, and weather prediction for extreme events, to prepare and produce useful results for our changing world.
