Extreme temperatures ‘especially likely for next four years’

Extreme temperatures ‘especially likely for next four years’

SOURCE: The Guardian DATE: August 14, 2018 SNIP: The world is likely to see more extreme temperatures in the coming four years as natural warming reinforces manmade climate change, according to a new global forecasting system. Following a summer of heatwaves and forest fires in the northern hemisphere, the study in the journal Nature Communications suggests there will be little respite for the planet until at least 2022, and possibly not even then. Rising greenhouse gas emissions are steadily adding to the upward pressure on temperatures, but humans do not feel the change as a straight line because the effects are diminished or amplified by phases of natural variation. From 1998 to 2010, global temperatures were in a “hiatus” as natural cooling (from ocean circulation and weather systems) offset anthropogenic global warming. But the planet has now entered almost the opposite phase, when natural trends are boosting man-made effects. [T]he statistical upward nudge from natural variation this year is twice as great of that of long-term global warming. Next year, it is likely to be three times...
A new study based on evidence from past warm periods suggests global warming may be double what is forecast.

A new study based on evidence from past warm periods suggests global warming may be double what is forecast.

SOURCE: UNSW Sydney and Nature Geoscience DATE: July 5, 2018 SNIP: Future global warming may eventually be twice as warm as projected by climate models and sea levels may rise six metres or more even if the world meets the 2°C target, according to an international team of researchers from 17 countries. “Observations of past warming periods suggest that a number of amplifying mechanisms, which are poorly represented in climate models, increase long-term warming beyond climate model projections,” said lead author, Prof Hubertus Fischer of the University of Bern. “This suggests the carbon budget to avoid 2°C of global warming may be far smaller than estimated, leaving very little margin for error to meet the Paris targets.” “Even with just 2°C of warming – and potentially just 1.5°C – significant impacts on the Earth system are profound,” said co-author Prof Alan Mix of Oregon State University. “We can expect that sea-level rise could become unstoppable for millennia, impacting much of the world’s population, infrastructure and economic activity.” Yet these significant observed changes are generally underestimated in climate model projections that focus on the near term. Compared to these past observations, climate models appear to underestimate long term warming and the amplification of warmth in Polar Regions. “Climate models appear to be trustworthy for small changes, such as for low emission scenarios over short periods, say over the next few decades out to 2100. But as the change gets larger or more persistent, either because of higher emissions, for example a business-as-usual-scenario, or because we are interested in the long term response of a low emission scenario, it appears they...
How clouds complicate global warming

How clouds complicate global warming

SOURCE: Cosmos Magazine DATE: July 2, 2018 SNIP: Clouds are wispy evanescent things, beloved of poets and daydreamers. They may also determine whether civilisation as we know it survives the 21st century. Depending on how clouds react to global warming, they could cool or cook the planet. But, so far, we haven’t been able to predict which way they will swing. That’s a big problem for our ability to prepare for what’s coming. At issue is climate sensitivity, which measures how much the temperature changes if the amount of carbon dioxide (CO2) in the atmosphere doubles. In 2014 the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) estimated this number somewhere between 1.5 and 4.5°C. This huge range comes down almost entirely to the effect of clouds. By amplifying warming or reining it in, clouds could make the difference between a 2°C increase – where sea levels rise a metre or more and deadly heatwaves are predicted – and a truly catastrophic 4.5°C – which, according to the IPCC, means widespread extinctions, global food supplies at risk and many parts of the planet too hot to live in. [Fascinating article, I recommend reading the whole...
Global warming set to exceed 1.5°C, slow growth – U.N. draft

Global warming set to exceed 1.5°C, slow growth – U.N. draft

SOURCE: Reuters DATE: June 14, 2018 SNIP: Global warming is on course to exceed the most stringent goal set in the Paris agreement by around 2040, threatening economic growth, according to a draft report that is the U.N.’s starkest warning yet of the risks of climate change. Governments can still cap temperatures below the strict 1.5 degrees Celsius (2.7° Fahrenheit) ceiling agreed in 2015 only with “rapid and far-reaching” transitions in the world economy, according to the U.N.’s Intergovernmental Panel on Climate Change (IPCC). The final government draft, obtained by Reuters and dated June 4, is due for publication in October in South Korea after revisions and approval by governments. It will be the main scientific guide for combating climate change. “If emissions continue at their present rate, human-induced warming will exceed 1.5°C by around 2040,” according to the report, which broadly reaffirms findings in an earlier draft in January but is more robust, after 25,000 comments from experts and a wider pool of scientific literature. Temperatures are already up about 1°C (1.8°F) and are rising at a rate of about 0.2°C a decade, according to the draft, requested by world leaders as part of the Paris...
A city in Pakistan may have just endured the hottest April temperature ever observed on Earth

A city in Pakistan may have just endured the hottest April temperature ever observed on Earth

SOURCE: Washington Post DATE: May 1, 2018 SNIP: On Monday, a city in the southern part of Pakistan soared to 122.4 degrees (50.2 Celsius). This might just be the highest temperature ever reliably measured on the planet during April. This is the second straight month in which Nawabshah has set a new monthly temperature record for Pakistan. In late March, a heat wave pushed the temperature there to a national record of 113.9 degrees for the month. Several other countries in Asia also established March record highs during the hot spell from the 29th to the 31st. As concentrations of heat-trapping gases continue to build in the atmosphere due to human activity, the expectation is for an increase in the intensity, frequency and duration of hot...