27 July 2017, Climate News Network, Geo-engineers propose climate compromise. Humans have unintentionally changed the world and turned up the temperature. A climate compromise might turn down the heat. Geo-engineering, the deliberate alteration of the planet to undo its inadvertent alteration by humans over the past 200 years, is back on the scientific agenda, with a climate compromise suggested as a possible solution. One group wants to turn down the global thermostat and reverse the global warming trend set in train by greenhouse gases released by fossil fuel combustion, by thinning the almost invisible cirrus clouds that trap radiation and keep the planet warm. Another group proposes to inject sulphur particles into the stratosphere, and keep on doing so for 160 years, to block enough sunlight and lower the planetary temperature. And a third group wants to see a cocktail of both approaches: thin the high cirrus clouds that stop heat from escaping, and at the same pump particles into the stratosphere to scatter the incoming sunlight and limit the disadvantages of each approach by mixing them. The verb “wants” in all three studies is neither fair nor appropriate: all three groups concede that the healthy answer is for humans to fulfil the pledge made in 2015, and start to reduce fossil fuel emissions so drastically that global average temperatures stay well below the 2°C maximum rise agreed by 197 nations at the Paris climate conference. Read More here
Category Archives: The Science
18 July 2017, Climate Central, At Midway Point, 2017 Is 2nd-Hottest Year on Record. At the halfway point of the year, 2017 remains the second-hottest year to date — a surprise given the demise of the El Niño that helped boost temperatures to record levels last year. The continued near-record warmth is a marker of just how much global temperatures have risen thanks to the greenhouse gases accumulating in the atmosphere from fossil fuel use. “Personally, I wasn’t expecting it to be as warm as it has been,” Ahira Sanchez-Lugo, a National Oceanic and Atmospheric Administration climate scientist, said in an email. “After the decline of the strong El Niño I was expecting the values to drop a bit and rank among the top five warmest years. This year has been extremely remarkable.” The odds are good that 2017 will stay in second place through the end of the year, and it is even more likely that it will remain in at least the top three hottest years. NOAA released its global temperature data for June on Tuesday, and ranked June as the third warmest in its records. The four-warmest Junes in its records have all happened in the past four years. (NASA, which released its June numbers on Friday, ranked June as the fourth hottest. The two agencies handle the data slightly differently, which can lead to small differences in their rankings, though they strongly agree on recent warming.) The hotspots around the world for June included central Asia and western and central Europe. A searing heat wave in western Europe that helped fuel deadly wildfires in Portugal was made up to 10 times more likely because of Earth’s rising temperature, according to a recent study done in partnership with Climate Central. Read More here
14 July 2017, Nature Communications, The unprecedented 2015/16 Tasman Sea marine heatwave. The Tasman Sea off southeast Australia exhibited its longest and most intense marine heatwave ever recorded in 2015/16. Here we report on several inter-related aspects of this event: observed characteristics, physical drivers, ecological impacts and the role of climate change. This marine heatwave lasted for 251 days reaching a maximum intensity of 2.9 °C above climatology. The anomalous warming is dominated by anomalous convergence of heat linked to the southward flowing East Australian Current. Ecosystem impacts range from new disease outbreaks in farmed shellfish, mortality of wild molluscs and out-of-range species observations. Global climate models indicate it is very likely to be that the occurrence of an extreme warming event of this duration or intensity in this region is respectively ≥330 times and ≥6.8 times as likely to be due to the influence of anthropogenic climate change. Climate projections indicate that event likelihoods will increase in the future, due to increasing anthropogenic influences. Read More here
13 July 2017, Climate Central, Greenhouse Gases Are Rapidly Changing the Atmosphere. Humanity’s grand experiment in the atmosphere continues, and a new report documents just how far it’s gone. On Tuesday, the National Oceanic and Atmospheric Administration released its annual index of 20 key greenhouse gases. It shows that their direct influence on the climate has risen 140 percent since 1750, with 40 percent of that rise coming in just the past 26 years. That increase is almost entirely due to human activities and has caused the planet to warm 1.8°F (1°C) above pre-industrial temperatures. The index takes greenhouse gas measurements from about 80 ships and observatories around the world — gathered in all their parts per million and parts per billion glory — and boils them down into a simple numerical index, which defines the rise from 1700-1990 as 100 percent or simply 1. This year’s number: 1.4. It’s a simple number that contains multitudes. For example, carbon dioxide’s influence on the climate has increased 54 percent overall since 1990. The four other major greenhouse gases in the index, which include nitrous oxide, methane and two types of chlorofluorocarbons, are responsible for 42 percent of the increase with 15 minor greenhouse gases accounting for the missing 4 percent. Carbon dioxide has risen rapidly in the atmosphere, with 2016 marking the second-largest annual increase ever observed at the Mauna Loa Observatory, the world’s main measuring station. This May, monthly carbon dioxide peaked at 409.65 parts per million. That’s a record high and a mark unseen in human history. If emissions continue on their current trend, the atmosphere will hit a state unseen in 50 million years. A bright spot in the report is the decline of chlorofluorocarbons’ warming influence on the planet. The chemicals were commonly used as refrigerants until the Montreal Protocol banned them in 1989. The treaty came about because they deplete the protective ozone layer, but phasing them out has also helped reduce their warming impact on the climate. Read More here