8 June 2017, The Conversation, What is a pre-industrial climate and why does it matter? Over the past few days there has been a lot of talk about the Paris climate agreement, from which the United States is planning to withdraw. Although this is a setback, there is still near-complete consensus from the world’s governments that a strong effort to tackle climate change is needed. The Paris Agreement aims to limit global warming relative to a pre-industrial baseline. Its precise commitment is: Holding the increase in the global average temperature to well below 2℃ above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5℃ above pre-industrial levels, recognising that this would significantly reduce the risks and impacts of climate change. But this begs the question: what are “pre-industrial levels”? Clearly, if we’re aiming to limit global warming to 1.5℃ or 2℃ above a certain point, we need a common understanding of what we’re working from. But the Paris Agreement doesn’t provide a definition. This becomes key as governments expect climate scientists to coherently compare different plans to reach their Paris targets. It’s crucial to be clear on what researchers mean when we say “pre-industrial”, and what assumptions our projections are based on. Of course, as the chart below shows, no matter which baseline we use it’s clear there’s been a drastic rise in global temperature over the last century. Read More here
Category Archives: The Science
1 June 2017, The Conversation, Global stocktake shows the 43 greenhouse gases driving global warming. The most comprehensive collection of atmospheric greenhouse gas measurements, published today, confirms the relentless rise in some of the most important greenhouse gases. The data show that today’s aggregate warming effect of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) is higher than at any time over the past 800,000 years, according to ice core records. Building on half a century of atmospheric measurements by the international research community, we compiled and analysed the data as part of a group of international scientists, led by Malte Meinshausen from the University of Melbourne in collaboration with CSIRO. Together, the data provide the most compelling evidence of the unprecedented perturbation of Earth’s atmosphere. They clearly show that the growth of greenhouse gases began with the onset of the industrial era around 1750, took a sharp turn upwards in the 1950s, and still continues today. Research has demonstrated that this observed growth in greenhouse gases is caused by human activities, leading to warming of the climate – and in fact more than the observed warming, because part of the effect is currently masked by atmospheric pollution (aerosols). The new collection of records comes from measurements of current and archived air samples, air trapped in bubbles in ice cores, and firn (compacted snow). The data cover the past 2,000 years without gaps, and are the result of a compilation of measurements analysed by dozens of laboratories around the world, including CSIRO, the Bureau of Meteorology’s Cape Grim Station, NOAA, AGAGE and the Scripps Institution of Oceanography, among others. Read More here
31 March 2017, Climate Central, ‘Critical’ NASA Climate Missions Targeted in Budget Cuts. In his most recent weekly address, President Trump praised NASA’s “mission of exploration and discovery” and its ability to allow mankind to “look to the heavens with wonder and curiosity.” But left out of his statements was the work NASA does to peer back at our home planet and unravel its many remaining mysteries — a mission targeted for cuts in his administration’s budget outline released earlier this month. In a budget otherwise scant on specifics, four climate-related NASA satellite missions were proposed for termination, including one already in orbit. Those missions are aimed not only at helping scientists learn more about key parts of the climate system and how global warming is changing them, but also at practical matters such as monitoring the health of the nation’s coastal waters and providing earlier warnings of drought stress in crops. The proposed cancellations mesh with statements made by Trump, administration officials and some members of Congress who have argued that NASA should be focused on outer space and leave the job of observing Earth to other agencies. But NASA’s unparalleled experience and expertise in developing new observational technologies and launching satellites makes it a crucial part of the Earth science enterprise, many experts say. Read More here
27 March 2017, The Guardian, Trump presidency ‘opens door’ to planet-hacking geoengineer experiments. As geoengineer advocates enter Trump administration, plans advance to spray sun-reflecting chemicals into atmosphere. Harvard engineers who launched the world’s biggest solar geoengineering research program may get a dangerous boost from Donald Trump, environmental organizations are warning. Under the Trump administration, enthusiasm appears to be growing for the controversial technology of solar geo-engineering, which aims to spray sulphate particles into the atmosphere to reflect the sun’s radiation back to space and decrease the temperature of Earth. Sometime in 2018, Harvard engineers David Keith and Frank Keutsch hope to test spraying from a high-altitude balloon over Arizona, in order to assess the risks and benefits of deployment on a larger scale. Keith cancelled a similar planned experiment in New Mexico in 2012, but announced he was ready for field testing at a geoengineering forum in Washington on Friday. “The context for discussing solar geoengineering research has changed substantially since we planned and funded this forum nearly one year ago,” a forum briefing paper noted. While geoengineering received little favour under Obama, high-level officials within the Trump administration have been long-time advocates for planetary-scale manipulation of Earth systems. David Schnare, an architect of Trump’s Environmental Protection Agency transition, has lobbied the US government and testified to Senate in favour of federal support for geoengineering. He has called for a multi-phase plan to fund research and conduct real-world testing within 18 months, deploy massive stratospheric spraying three years after, and continue spraying for a century, a duration geoengineers believe would be necessary to dial back the planet’s temperature. Geoengineers argue that such methods would be an inexpensive way to reduce global warming, but scientists have warned it could have catastrophic consequences for the Earth’s weather systems. Scientific modelling has shown that stratospheric spraying could drastically curtail rainfall throughout Asia, Africa and South America, causing severe droughts and threatening food supply for billions of people. Read More here