If the World is Warming, How can we have very cold weather?Global warming refers to the long-term world-wide average. Redistribution of energy from one part of the planet to another may make some areas warmer and others cooler. For example, in the northern hemisphere 2009-2010 winter, some areas experienced extreme cold. However, if you look at the distribution of northern hemisphere temperatures, what happened was that the Arctic warmed considerably. Look at the image: the Arctic region shows strong warming, with Greenland considerably warmer than usual (more accurately, less chilly), yet Northern Europe and North America are large local areas of cooling. Possibly this effect caused cold air to move south, but in any case, the cooler overall northern hemisphere in the most inhabited regions has hit the news, a slightly misleading picture when you look at the whole map.
Dead Zones
A dead zone is part of the ocean where oxygen levels are too low (less than 2 parts per million) to support life, or anoxic. Here is a site at Montana State University that provides some information. For more, see NASA's information on dead zones. Algal blooms can make part of an ocean anoxic. In an extreme case, about 251-million years ago, the oceans became widely anoxic, as part of a mass extinction event at the boundary between the Permian and Triassic though probably that event had different causes.
Life In Your Back Yard
Want to find out if there are endangered species or unwanted alien invaders somewhere, or just check out who or what your wild neighbours are? The federal environment department has a great tool for finding these things out. Click the "Interactive Map" link, find your area of interest on the map, click Report and use the mouse to drag out a rectangle on the map.
Electric cars – in the early days of motoring, a mainstream option – are making a comeback, with variations such as hybrids and plug-in hybrids. But how green are they really? Here's an article with more detail. Check out Tesla’s first sedan. A UK company, Riversimple, has some interesting ideas on how to build an ultra-efficient car using a hydrogen fuel cell. I remain unconvinced of the hydrogen economy because hydrogen takes a lot of energy to produce, but Riversimple has some interesting ideas, like leasing the cars rather than selling them as a way of avoiding the false economy of planned obsolescence.
Smart Grid
Something that will be talked about increasingly is managing energy use more intelligently not only to be more efficient but to fit swings in demand to swings in supply better, as a remedy for the intermittency of some modes of renewable energy. Look out for articles about the smart grid such as this one.
Electric Vehicles
Now that the Obama administration is talking up clean energy, there's been an explosion of interest in electric vehicles, so much so that rather than summarize articles, I’ll list pointers to them here as I encounter them:
- Willie D. Jones. New Electric Power Train Promises 160-km All-Electric Range—on a Bus! IEEE Spectrum, April 2009
Biochar
Biochar is the idea of burning carbon-containing materials in low oxygen (pyrolysis), resulting in charcoal that can be buried in the ground, improving the soil while sequestering carbon and reducing nitrous oxide (potent greenhouse gas) emissions from the soil. Biochar can also be used to produce biofuels as a byproduct. Here’s a nice YouTube summary of Australian work on biochar:
“Clean” coal
Various projects claim to be cleaning up coal. Carbon sequestration is one of the buzz words. The theory is that you can bury the CO2 deep underground. In practice, to do so on a significant scale would be very hard. The perceived need for carbon sequestration arises from the incorrect perception that a coal producing country like Australia cannot survive a transition away from coal, a claim that is hotly contested even by former coal supporters. Here are some contrary views:
- Quarry vision: why clean coal isn't the answer, ABC Radio National, 25 March 2009
- Quarry vision: why coal is no longer important, ABC Radio National, 25 March 2009
Mining stalwart sees no future in carbon plan, Sydney Morning Herald, 25 April 2009
Some obstacles: worldwide emissions would amount to around 30km3 per year even compressed down to a liquid. One power station would be a lot less but still a vast volume of toxic gas to handle. Pumping it out at high temperature through a high smoke stack dissipates it into the air, and turbulence mixes it into the atmosphere quickly. A cold leak at ground level on the other hand will not dissipate fast, and can kill people in large numbers, as occasionally happens as a result of volcanic processes. Here is a detailed critique I wrote of a “clean coal” proposal for Felton in Queensland. And here is a Coen brothers ad featuring their take on clean coal:
Forest management and climate change
The forestry lobby is big on the benefits of harvesting timber. Cutting down trees, they claim, is somehow good because new growth will sequester even more carbon. The reality is a lot more complex than that; logging old growth is almost always a net loss, and managing plantations for the best overall return on carbon emissions takes careful management. This Forest, Carbon, Climate Myths slide show covers most of the major issues.
Regenerating lost forests
Watch biologist Willie Smits explain how he re-grew clearcut rainforest in Borneo, saving local orangutans – and at the same time creating work for the locals. Ignore the car ads.
Past greenhouse warming
You’ve heard about links between carbon emissions and greenhouse warming in the past. Much is written about the recent past, but there haven’t been major cases of carbon emissions capable of causing climate change for over a million years. If we go back for example to the Palaeocene–Eocene Thermal Maximum (PETM) about 55-million years ago, we find an event where very rapid climate change was caused by a big increase in the carbon dioxide content of the atmosphere. More here (PDF). The real big one though is the Permian-Triassic (P-Tr) extinction. This was one of the biggest climate change events since complex life began and was also by far the largest extinction, with over 90% of marine species disappearing, and around 70% of land vertebrates pecies becoming extinct. This is also the only known insect mass extinction. That long ago, the primary cause is hard to pin down, but it seems likely that one of the biggest volcanic eruptions ever played a role. Not only did these eruptions spew out vast quantities of CO2 but they may have set fire to huge coal fields, and released enormous quantities of methane from the sea (where it becomes trapped in a crystallised form of water, as methane clathrates). Wikipedia has a good summary.
Snowball earth
We’ve all heard of global warming. What of the opposite, an event where the planet cools – even possibly to the extent of the entire planet becoming a ball of ice? It’s happened three times before, but is unlikely to happen again. For one thing, the sun’s output is increasing at a rate of 6% per billion years, and the last snowball world was over 600-million years ago. Scientists in recent times have investigated the possibility that a repetition could be caused by an asteroid strike such as that which wiped out the dinosaurs, or a nuclear war. Such events could cause global dimming, by cutting the amount of solar energy that reaches the lower atmosphere. Few scientists consider such a scenario likely under current conditions. Read more here.
More common global cooling
What of less dramatic global cooling than the snowball earth scenario? A well-known example: the Cretaceous-Tertiary (K-T) extinction wiped out dinosaurs as well as about half of all species, as a consequence most likely of an asteroid strike, that filled the upper atmosphere with fine particles, much like the nuclear winter scenario. In this case the cooling was not extreme enough to cause a snowball earth. Here is a paper (PDF) showing how the oceans could have cooled over a period of around 2000 years following the impact. Global cooling had a brief flurry of attention in the 1970s partially motivated by concerns of a nuclear winter but also by concerns of the global dimming effect of industrial pollution, before scientists broadly agreed that the temperature record was pointing at global warming. Is this pollution-caused global dimming effect a possible solution to global warming? No. For a start, the global dimming of the mid to late twentieth century was caused by fine sulphate particles (called aerosols) in the upper atmosphere, caused by industrial pollution, that reflected heat. These particles precipitate out as acid rain. So not only is this not a long-term effect, but it has other harmful consequences.
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