4 November 2015, New York Times, The Tough Realities of the Paris Climate Talks. In less than a month, delegates from more than 190 countries will convene in Paris to finalize a sweeping agreement intended to constrain human influence on the climate. But any post-meeting celebration will be tempered by two sobering scientific realities that will weaken the effectiveness of even the most ambitious emissions reduction plans that are being discussed. The first reality is that emissions of carbon dioxide, the greenhouse gas of greatest concern, accumulate in the atmosphere and remain there for centuries as they are slowly absorbed by plants and the oceans. This means modest reductions in emissions will only delay the rise in atmospheric concentration but will not prevent it. Thus, even if global emissions could be reduced by a heroic average 20 percent from their “business as usual” course over the next 50 years, we would be delaying the projected doubling of the concentration by only 10 years, from 2065 to 2075. This is why drastic reductions would be needed to stabilize human influences on the climate at supposed “safe” levels. According to scenarios used by the United Nations Intergovernmental Panel on Climate Change, global annual per capita emissions would need to fall from today’s five metric tons to less than one ton by 2075, a level well below what any major country emits today and comparable to the emissions from such countries as Haiti, Yemen and Malawi. For comparison, current annual per capita emissions from the United States, Europe and China are, respectively, about 17, 7 and 6 tons. The second scientific reality, arising from peculiarities of the carbon dioxide molecule, is that the warming influence of the gas in the atmosphere changes less than proportionately as the concentration changes. As a result, small reductions will have progressively less influence on the climate as the atmospheric concentration increases. The practical implication of this slow logarithmic dependence is that eliminating a ton of emissions in the middle of the 21st century will exert only half of the cooling influence that it would have had in the middle of the 20th century. Read More here
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3 November 2015, ITV, What you need to know about the Paris climate change summit. A meeting later this month will see 190 nations convene in Paris to try and work out a way to tackle climate change. Here is what you need to know about it: What is the Paris meeting? On November 30, 190 nations will gather for two weeks to try and work out a deal to tackle climate change. The aim will be to find a way to reduce the global emissions of greenhouse gases – such as carbon dioxide and methane – over the coming decades to avoid the world’s average temperature increasing by no more than 2C by the end of this century. That’s compared to the world’s temperature before the industrial revolution around 150 years ago, when parts of the world began the mass burning of fossil fuels. Go above that rise in temperature, say scientists, and we tip over into “dangerous climate change” where there will be drastic increases in floods, storms, heatwaves and other catastrophic and irreversible environmental changes around the world. These will disproportionately affect the poorest parts of the world, those least able to adapt. At the moment, if the world does nothing, it is on course for a 5C temperature rise by 2100. This might not seem like much, but bear in mind that the average difference between now and the Earth’s previous Ice Age was around 5C. Read More here
3 November 2015, Bloomberg View, What Economists Don’t Get About Climate Change. Economists tend to see climate change as a big optimization problem: Weigh the potential costs of future disasters against the benefits of fossil-fueled economic growth, and find a price of carbon that will balance the two. Unfortunately, it’s an illusory goal. The Cost of Carbon Consider, for example, a recent study by Yale University’s Kenneth Gillingham and colleagues. Using a collection of so-called “integrated” models of climate and the economy, they seek to get a better handle on how various uncertainties — in weather, population growth and technological development — might affect the price that policy makers should put on carbon. Their conclusion: No matter what happens, the optimal price in 2020 would probably be no more than about $50 per ton. The paper’s appearance may be timed to influence policy makers at the United Nations Climate Change Conference in Paris, which begins at the end of this month. It really shouldn’t, because it feigns certainty in areas where none is to be had. Granted, such integrated models include some realistic climate physics and economics. Yet their builders inevitably face crucial questions about which we know very little. For example, just how sensitive are global temperatures to the addition of further carbon dioxide? And how much economic damage can we expect from a temperature rise of, say, 2 degrees or 5 degrees? Read More here
3 November 2015, The Conversation, As drought looms, the Murray-Darling is in much healthier shape – just don’t get complacent. Melbourne Cup Day is a significant day in the history of water policy in Australia. The first Tuesday in November 2006 saw the then Prime Minister John Howard intervene decisively in the growing drought crisis in the southern Murray-Darling Basin (MDB). Nine years on, the spectre of drought is back. The Murray Darling Basin Authority’s weekly reports show inflows into the River Murray (which can be seen as a proxy for the southern MDB) during the year to end September 2015 were the among the lowest on record. And the Bureau of Meteorology’s National Climate and Water Briefing last week suggests a warm and dry summer in prospect in the southern MDB, amid a still strengthening El Niño. Yet there are reasons to believe that these past nine years of stronger Commonwealth involvement have left the MDB much better placed to withstand an escalating drought. That said, there is no room for complacency, and continuing Commonwealth commitment is still needed if those hard-won gains are to be retained. Read More here