Choices made now are critical for the future of our ocean and cryosphere

Choices made now are critical for the future of our ocean and cryosphere

SOURCE: IPCC DATE: September 25, 2019 SNIP: The latest Intergovernmental Panel on Climate Change (IPCC) Special Report highlights the urgency of prioritizing timely, ambitious and coordinated action to address unprecedented and enduring changes in the ocean and cryosphere. Global warming has already reached 1°C above the pre-industrial level, due to past and current greenhouse gas emissions. There is overwhelming evidence that this is resulting in profound consequences for ecosystems and people. The ocean is warmer, more acidic and less productive. Melting glaciers and ice sheets are causing sea level rise, and coastal extreme events are becoming more severe. People in mountain regions are increasingly exposed to hazards and changes in water availability, the report said. Glaciers, snow, ice and permafrost are declining and will continue to do so. This is projected to increase hazards for people, for example through landslides, avalanches, rockfalls and floods. Smaller glaciers found for example in Europe, eastern Africa, the tropical Andes and Indonesia are projected to lose more than 80% of their current ice mass by 2100 under high emission scenarios. Glaciers and ice sheets in polar and mountain regions are losing mass, contributing to an increasing rate of sea level rise, together with expansion of the warmer ocean. While sea level has risen globally by around 15 cm during the 20th century, it is currently rising more than twice as fast – 3.6 mm per year – and accelerating, the report showed. Sea level will continue to rise for centuries. It could reach around 30-60 cm by 2100 even if greenhouse gas emissions are sharply reduced and global warming is limited to well...
Climate change: Impacts ‘accelerating’ as leaders gather for UN talks

Climate change: Impacts ‘accelerating’ as leaders gather for UN talks

SOURCE: BBC DATE: September 22, 2019 SNIP: The signs and impacts of global heating are speeding up, the latest science on climate change, published ahead of key UN talks in New York, says. The data, compiled by the World Meteorological Organization (WMO), says the five-year period from 2014 to 2019 is the warmest on record. Sea-level rise has accelerated significantly over the same period, as CO2 emissions have hit new highs. The climate statement is a pull-together of the latest science on the causes and growing impacts of unprecedented levels of warming seen in recent years. Recognising that global temperatures have risen by 1.1 degrees C since 1850, the paper notes they have gone up by 0.2C between 2011 and 2015. This is as a result of burgeoning emissions of carbon, with the amount of the gas going into the atmosphere between 2015 and 2019 growing by 20% compared with the previous five years. Perhaps most worrying of all is the data on sea-level rise. The average rate of rise since 1993 until now is 3.2mm per year. However, from May 2014 to 2019 the rise has increased to 5mm per year. The 10-year period from 2007-2016 saw an average of about 4mm per year. “Sea-level rise has accelerated and we are concerned that an abrupt decline in the Antarctic and Greenland ice sheets, which will exacerbate future rise,” said WMO secretary general Petteri Taalas. The report also highlights the threats to the oceans, with more than 90% of the excess heat caused by climate change ending up in the waters. The WMO analysis says 2018 had the highest...
Scientists Have Been Underestimating the Pace of Climate Change

Scientists Have Been Underestimating the Pace of Climate Change

SOURCE: Scientific American DATE: August 19, 2019 SNIP: Recently, the U.K. Met Office announced a revision to the Hadley Center historical analysis of sea surface temperatures (SST), suggesting that the oceans have warmed about 0.1 degree Celsius more than previously thought. The need for revision arises from the long-recognized problem that in the past sea surface temperatures were measured using a variety of error-prone methods such as using open buckets, lamb’s wool–wrapped thermometers, and canvas bags. It was not until the 1990s that oceanographers developed a network of consistent and reliable measurement buoys. Then, to develop a consistent picture of long-term trends, techniques had to be developed to compensate for the errors in the older measurements and reconcile them with the newer ones. The Hadley Centre has led this effort, and the new data set—dubbed HadSST4—is a welcome advance in our understanding of global climate change. But that’s where the good news ends. Because the oceans cover three fifths of the globe, this correction implies that previous estimates of overall global warming have been too low. Moreover it was reported recently that in the one place where it was carefully measured, the underwater melting that is driving disintegration of ice sheets and glaciers is occurring far faster than predicted by theory—–as much as two orders of magnitude faster—–throwing current model projections of sea level rise further in doubt. These recent updates, suggesting that climate change and its impacts are emerging faster than scientists previously thought, are consistent with observations that we and other colleagues have made identifying a pattern in assessments of climate research of underestimation of certain key...
IPCC Report Shows Food System Overhaul Needed to Save the Climate

IPCC Report Shows Food System Overhaul Needed to Save the Climate

SOURCE: Inside Climate News DATE: August 8, 2019 SNIP: Negotiators for the world’s governments signed off on a report Wednesday that describes in alarming detail how agriculture, deforestation and other human impacts on lands are transforming the climate. The report, from the United Nations’ Intergovernmental Panel on Climate Change (IPCC), shows the urgent need to overhaul the global food system to help control climate-warming emissions. Written by more than 100 scientists from around the globe, it takes an unprecedented look at the impacts of climate change on lands and the effects of land use on the climate. The authors say that the entire food production system, with transportation and packaging included, accounts for as much as 37 percent of total greenhouse gas emissions, and that better land use, less-meat-intensive diets and eliminating food waste should be global priorities, crucial to the immediate, all-out effort needed to forestall a climate catastrophe. “There’s no doubt the window is closing rapidly,” said Pamela McElwee, one of the report’s authors and a professor of human ecology at Rutgers University. “That’s a key message of this...
Climate Change Is Taking a Bigger Toll on Our Food, Water, and Land Than We Realized

Climate Change Is Taking a Bigger Toll on Our Food, Water, and Land Than We Realized

SOURCE: Mother Jones DATE: August 8, 2019 SNIP: As the planet warms, parts of the world face new risks of food and water shortages, expanding deserts, and land degradation, warns a major new report from the United Nations’ Intergovernmental Panel on Climate Change. Those effects are already underway, and some of them could soon become irreversible. The changing climate has already likely contributed to drier climates in South and East Asia, North Africa, and the Middle East, reducing the food and water supply. In 2015, about 500 million people lived in dry areas that experienced desertification in recent decades as a result of human activities. Those problems are only going to get worse as climate change continues to take its toll. “Global warming has led to shifts of climate zones in many world regions, including expansion of arid climate zones and contraction of polar climate zones,” the IPCC says in the report, released Thursday. With high confidence, it adds, “Climate change has already affected food security due to warming, changing precipitation patterns, and greater frequency of some extreme events.” The new report focuses on land, which covers 30 percent of the Earth’s surface and is warming nearly twice as fast as the planet...