It is commonly understood that ecosystems have been taking up more carbon dioxide (CO2) as the concentration of atmospheric CO2 increases and the climate changes. The progressive increase in CO2 uptake by terrestrial ecosystems is generally thought to continue until 2030, when the trend is expected to reverse due to ecosystem damage. However, Dr. James C. Curran and Dr. Samuel A. Curran (2016) have found evidence that the trend may have already begun to reverse. They base this on analysis of the atmospheric CO2 measurements taken between 1958 and 2015 from the Mauna Loa observatory in Hawaii, known as the Keeling Curve. These data show a continual rise in atmospheric CO2 levels within a pattern of intra-annual fluctuation. The intra-annual fluctuation consists of decreased atmospheric CO2 levels throughout the summer months (Northern Hemisphere), and increased atmospheric CO2 throughout the rest of the year. Continue reading →
Because the Earth’s atmosphere intermixes globally, all areas of the globe are equally exposed to greenhouse gas emissions (GHGs). However, some countries are more vulnerable to the effects of these emissions, while some countries release more GHGs into the atmosphere than others. Althor et al. (2016) compare each country’s vulnerability to climate change to its creation of GHGs for the years 2010 and 2030. They found that the countries least vulnerable to climate change were higher GHG emitters, and the most vulnerable countries were least responsible for GHG emissions. By 2030 the inequity will have worsened. The authors call for climate change policies that place more responsibility for mitigating climate change on the high-emitters. Continue reading →
The peatlands and tundras of the Arctic perform vital ecosystem services to the earth through their ability to sequester carbon (CO2) and methane (CH4) and function as a carbon sink. The ability of the permafrost in the peatlands and tundra ecosystems of the Arctic to continue to function as a natural reservoir for carbon and methane may be disrupted by rising global temperatures that increase the rate of soil decomposition. Watts et al. (2014) integrate a terrestrial carbon flux (TCF) model to include a newly developed CH4 emissions algorithm. The new TCF model simultaneously assesses CO2 and CH4 fluctuations and the corresponding net ecosystem carbon balance (NECB), which is contingent upon gross primary productivity (GPP) subtracted from ecosystem respiration. The integrated TCF model uses data gathered through satellite remote sensors to assess fluxes in CO2 and CH4. Continue reading →
The consumption of food and beverages accounts for 22–31% of total private consumption greenhouse gas (GHG) emissions in the EU (Tukker et al. 2009). More specifically, the production of meat and dairy products tend to produce greater GHG emissions (Audsley et al. 2009). Saxe et al. (2012) examine how different diets, which are composed of different foods, are associated with varying potential GHG emissions. They use consequential Life Cycle Assessment to compare the emissions, or global warming potential (GWP), from food production for an Average Danish Diet (ADD), the Nordic Nutritional Recommendations (NNR), and a New Nordic Diet (NND), which was developed by the OPUS Project. They determined that the GHG emissions association with NNR and NND were lower than those associated with ADD, by 8% and 7%, respectively. When taking into account the transport of food, NND emissions are 12% less than ADD emissions. With regard to organic versus conventional food production, GHG emissions are 6% less for NND than for the ADD. Saxe et al. adjusted NND to include less beef and more organic produce, and they substituted meat with legumes, dairy products, and eggs, which made the diet more climate-friendly. As a result of this adjustment, the GHG emissions associated with NDD was 27% less than emissions for ADD. Continue reading →
Last week, in anticipation of the United Nations climate conference in New York, The Economist concluded that the single most important action to slow global warming so far has been enactment of the Montreal protocol. Say what? This isn’t on most environmentalists’ radar as an important factor. The Montreal protocol is the 1987 international agreement to save the ozone layer by phasing out Freon and other chlorofluorocarbons used in refrigeration. But these substances are powerful greenhouse gases as well as destroyers of stratospheric ozone, and the protocol caused millions of tonnes of them not to be released into the atmosphere. The article concludes that this avoided release of the greenhouse gas equivalent of 5.6 billion tonnes (bt) of CO2. This is about twice as much avoided CO2 as the next two most effective actions, global use of nuclear power (2.8 bt) and hydroelectricity (2.2 bt), and four times that of the fourth most effective action, China’s one-child policy (1.3 bt). I’m guessing that most of the 300,000 demonstrators in New York last week are not proposing an expansion of these latter three items, but their past effectiveness does make one think. The most effective actions taken specifically to reduce energy usage and CO2 emissions have been worldwide adoption of renewables (0.6 bt), US vehicle emissions standards (0.5 bt), and Brazil forest preservation (0.4 bt). The remaining 11 items on The Economist’s list are small potatoes, totaling less than 1 bt collectively. Continue reading →
In the middle of one of the worst fire seasons on record for Northern California comes a new modeling paper by scientists at CalTech’s Jet Propulsion Laboratory, the University of Idaho, and the US Forest Service Pacific Wildland Fire Sciences Laboratory predicting no effect of climate change on Northern California Very Large Wildfires (VLWFs), but potentially large increases in them in the Pacific Northwest and Rocky Mountains under future greenhouse gas (GHG) emissions scenarios. It may well be that the size of the Northern California fires won’t reach the threshold of 50,000 acres used in this study (the top 2% of wildland fires), but if these not-so-large fires are disturbing, then the prospect of even larger ones more frequently in much of the western US is even more so. Continue reading →
Nitrogen fertilizer, crucial for growing commercial crops, is based on ammonia made in factories using the energy- and CO2-intensive Haber-Bosch process; hydrogen is stripped off natural gas using steam, then reacted with nitrogen in the air. The process uses repeated cycling at high temperature and pressure, and consumes 2% of the world’s energy production. Stuart Licht and colleagues at George Washington University noticed, however, that a recently developed fuel cell using ammonia as a fuel and producing electricity as an output might be run in reverse: electricity in, ammonia out, with a whole lot less temperature and pressure (and energy) required. Even better, it wouldn’t need natural gas as a hydrogen source—with its attendant CO2 production—being able to get it from air and steam at a temperature lower than a household oven baking bread and at ambient pressure. Furthermore only simple materials would be required; molten sodium and potassium hydroxide (inexpensive commodity chemicals), nickel electrodes, and an iron oxide catalyst, all in a single pot.
After considerable experimentation with different temperatures, voltages, forms of iron oxide, Continue reading →