Even if we stay under 2C, extreme events -heat, floods, drought – will become more likely in the decades ahead. And if countries do not meet the Paris climate agreement goals, the risks will be even greater
Overall, up to 60% of locations across North America, Europe, East Asia and parts of southern South America would likely see at least a 3x and up to 5x increase in some areas increase in various extreme events, according to a Stanford study published yesterday in the journal Science Advances.
The country pledges to the Paris climate accord may put the world on track to warm by about 3 C, unless significantly greater climate action is promised—and soon.
Events like record-setting heat, extreme rainfall and drought will happen more frequently around the world even if global climate targets are met, new research suggests. And missing those targets could make the risk even worse.
…the pledges world nations have submitted under the Paris Agreement are likely still not enough to keep global temperatures within the 2 C threshold envisioned by the accord. Experts suggest that the pledges may put the world on track to warm by about 3 C, unless significantly greater climate action is promised—and soon.
“In addition to not meeting the global temperature target, those commitments also imply substantial increase in the probability of record-setting events,” said Noah Diffenbaugh, a Stanford University climate researcher and the new study’s lead author. “Not only hot events but wet events, and also in other regions of the world, dry events as well.”…
….Heat records are likely to be among the most sensitive to future climate change. Record-breaking nighttime temperatures have already been increasing across 90 percent of the studied areas, the research suggests, and these records may increase by at least fivefold across half of Europe and a quarter of East Asia.Extreme wet events and milder cold spells are also expected to increase throughout the world, and extreme dry events will see an uptick in certain regions, mainly in the midlatitudes.
Strengthening the Paris pledges could help significantly reduce the risks of extreme climate events, the new research suggests, although it warns that these events will still become more frequent in the future, even if temperature increases stay under 2 C.
….The findings, overall, carry a double warning. First, even with aggressive climate action, extreme climate events are likely to increase throughout much of the world—and human societies should brace themselves for that future, no matter what. But those mitigation efforts are still sorely needed, the research also suggests. Without them, the risks could be far more intense.
Noah S. Diffenbaugh, Deepti Singh, and Justin S. Mankin. Unprecedented climate events: Historical changes, aspirational targets, and national commitments. Science Advances, 14 Feb 2018 DOI: 10.1126/sciadv.aao3354
European national science academies report warns tepid emission cuts not enough.
A new European Academies Science Advisory Council (EASAC) report looks at a number of options, including reforestation, soil management, plankton fertilization, industrial CO2 capture plants, biofuels with emissions injected underground for storage, and even the boosting of bedrock weathering reactions.
The report’s conclusions: we have to develop carbon dioxide removal schemes more aggressively, but we also have to cut our emissions enough that we don’t rely on those schemes to save us.
….Those scenarios involved a substantial deployment of technologies to actively remove CO2 from the atmosphere. Without those technologies, we’re even further from sufficient emissions cuts.
That leaves us with a crucial question: can carbon dioxide removal techniques be scaled up to the necessary level in time? A new European Academies Science Advisory Council (EASAC) report—reviewed and endorsed by the national academies of more than two dozen countries—evaluates the outlook for carbon dioxide removal. And it’s not optimistic.…
….The EASAC report finds that few options look like they could scale up to three or four billion tons. And more importantly, none is on track to do so at this point. Reforestation and accumulating carbon in agricultural soils are probably the easiest options to make progress on, for example, but we’re currently still doing the opposite of these things: deforestation and soil degradation are adding to our greenhouse gas emissions, not counteracting them….
….The EASAC report’s conclusions are basically twofold: we have to develop carbon dioxide removal schemes more aggressively, but we also have to cut our emissions enough that we don’t rely on those schemes to save us….
Slashing emissions to Paris climate agreement targets could reduce impacts on CA vegetation 20-30% per new UC Davis, USGS, CDFW, NPS study
Cutting emissions so that global temperatures increase by no more than 2 degrees Celsius (3.2 degrees Fahrenheit) could reduce those impacts by half, with about a quarter of the state’s natural vegetation affected.
It projects that at current rates of greenhouse gas emissions, vegetation in southwestern California, the Central Valley and Sierra Nevada mountains becomes more than 50 percent impacted by 2100, including 68 percent of the lands surrounding Los Angeles and San Diego.
Areas projected to be more resilient include some coastal areas and parts of northwestern California.
Current levels of greenhouse gas emissions are putting nearly half of California’s natural vegetation at risk from climate stress, with transformative implications for the state’s landscape and the people and animals that depend on it, according to a study led by the University of California, Davis. However, cutting emissions so that global temperatures increase by no more than 2 degrees Celsius (3.2 degrees Fahrenheit) could reduce those impacts by half, with about a quarter of the state’s natural vegetation affected.
The study, published in the journal Ecosphere, asks: What are the implications for the state’s vegetation under a business-as-usual emissions strategy, where temperatures increase up to 4.5 degrees Celsius by 2100, compared to meeting targets outlined in the Paris climate agreement that limit warming to 2 degrees Celsius?
“At current rates of emissions, about 45-56 percent of all the natural vegetation in the state is at risk, or from 61,190 to 75,866 square miles,” said lead author James Thorne, a research scientist with the Department of Environmental Science and Policy at UC Davis. “If we reduce the rate to Paris accord targets, those numbers are lowered to between 21 and 28 percent of the lands at climatic risk.”…
…“This is the map of where we live,” Thorne said. “The natural landscapes that make up California provide the water, clean air and other natural benefits for all the people who live here. They provide the sanctuary for California’s high biodiversity that is globally ranked. This map portrays the level of climate risk to all of those things. In some cases, the transformation may be quite dramatic and visible, as is the case with wildfire and beetle outbreaks. In other cases, it might not be dramatically visible but will have impacts, nevertheless.”…
…the data is helping the agency understand not only which parts of the state are vulnerable to climate change, but also which areas are more resilient, such as some coastal areas and parts of northwestern California, so they can ensure they remain resilient….
Decades of diplomatic efforts to stem global warming have proven ineffectual because too many strategies have been taken off the table.
But what definitely won’t suffice is a climate strategy built out of wishful thinking: the proposition that countries can be cajoled and prodded into increasing their ambition to cut emissions further, and that laggards can be named and shamed into falling into line.
There is no momentum for investing in carbon capture and storage, since it could be seen as condoning the continued use of fossil fuels. Nuclear energy, the only source of low-carbon power ever deployed at the needed scale, is also anathema. Geoengineering, like pumping aerosols into the atmosphere to reflect the sun’s heat back into space, is another taboo. But eventually, these options will most likely be on the table, as the consequences of climate change come more sharply into focus…
Global emissions of greenhouse gases amounted to the equivalent of some 30 billion tons of carbon dioxide a year — excluding those from deforestation and land use. Worried about its accumulation, the gathered scientists and policymakers called on the world to cut CO2 emissions by a fifth.
That didn’t happen, of course. By 1997, when climate diplomats from the world’s leading nations gathered to negotiate a round of emissions cuts in Kyoto, Japan, emissions had risen to some 35 billion tons and the global surface temperature was roughly 0.7 degrees Celsius above the average of the late 19th century.
It took almost two decades for the next breakthrough. When diplomats from virtually every country gathered in Paris just over two years ago to hash out another agreement to combat climate change, the world’s surface temperature was already about 1.1 degrees Celsius above its average at the end of the 1800s. And greenhouse gas emissions totaled just under 50 billion tons….
…Climate diplomats in Paris didn’t merely reassert prior commitments to keep the world’s temperature less than 2 degrees above that of the “preindustrial” era — a somewhat fuzzy term that could be taken to mean the second half of the 19th century. Hoping to appease island nations like the Maldives, which are likely to be swallowed by a rising ocean in a few decades, they set a new “aspirational” ceiling of 1.5 degrees.
To stick to a 2 degree limit, we would have to start reducing global emissions for real within about a decade at most — and then do more. Half a century from now, we would have to figure out how to suck vast amounts of carbon out of the air. Keeping the lid at 1.5 degrees would be much harder still.
And yet, when experts tallied the offers made in Paris by all the countries in the collective effort, they concluded that greenhouse gas emissions in 2030 would exceed the level needed to remain under 2 degrees by 12 to 14 billion tons of CO2.
Are there better approaches? The “climate club” proposed by the Yale University economist William Nordhaus has the advantage of including an enforcement device, which current arrangements lack: countries in the club, committed to reducing carbon emissions, would impose a tariff on imports from nonmembers to encourage them to join.
Martin Weitzman of Harvard University supports the idea of a uniform worldwide tax on carbon emissions, which might be easier to agree on than a panoply of national emissions cuts. One clear advantage is that countries could use their tax revenues as they saw fit.
Mr. Barrett argues that the Paris agreement could be supplemented with narrower, simpler deals to curb emissions of particular gases — such as the 2016 agreement at a 170-nation meeting in Kigali, Rwanda, to reduce hydrofluorocarbon emissions — or in particular industries, like aviation or steel.
Maybe none of this would work. The climate club could blow up if nonmembers retaliated against import tariffs by imposing trade barriers of their own. Coordinating taxes around the world looks at least as difficult as addressing climate change. And Mr. Barrett’s proposal might not deliver a breakthrough on the scale necessary to move the dial.
…But what definitely won’t suffice is a climate strategy built out of wishful thinking: the proposition that countries can be cajoled and prodded into increasing their ambition to cut emissions further, and that laggards can be named and shamed into falling into line.
Inveigled by three decades of supposed diplomatic progress — coupled with falling prices of wind turbines, solar panels and batteries — the activists, technologists and policymakers driving the strategy against climate change seem to have concluded that the job can be done without unpalatable choices. And the group is closing doors that it would do best to keep open.
There is no momentum for investing in carbon capture and storage, since it could be seen as condoning the continued use of fossil fuels. Nuclear energy, the only source of low-carbon power ever deployed at the needed scale, is also anathema. Geoengineering, like pumping aerosols into the atmosphere to reflect the sun’s heat back into space, is another taboo.
But eventually, these options will most likely be on the table, as the consequences of climate change come more sharply into focus. The rosy belief that the world can reduce its carbon dependency over a few decades by relying exclusively on the power of shame, the wind and the sun will give way to a more realistic understanding of possibilities.
a broader range of scenarios is needed to support international policymakers in the target of limiting climate change to under 2°C above pre-industrial levels, and to avoid potential negative environmental and social consequences of carbon dioxide removal on a massive scale.
87% of the scenarios in the IPCC 5th Assessment Report that limit climate change to less than 2°C rely heavily on negative emissions in the second half of the century, with most of the carbon dioxide removal coming from a suite of technologies known as Bioenergy with Carbon Capture and Storage (BECCS)
massive implementation of these type of land-based carbon dioxide removal strategies would have impacts on both the environment and the food system, with previous research showing trade-offs for food security and environmental conservation.
reliance on future negative emissions to achieve climate goals may also fail to account for feedbacks in the climate system such as methane release from thawing permafrost, which are not yet fully understood
A new article lays the groundwork for alternative climate mitigation scenarios that place less reliance on unproven negative emissions technologies in the future.
…”Many currently used emissions pathways assume that we can slowly decrease fossil fuel emissions today and make up for it later with heavy implementation of negative emissions technologies,” says IIASA Ecosystems Services and Management Program Director Michael Obersteiner, lead author of the article. “This is a problem because it assumes we can put the burden on future generations — which is neither a realistic assumption nor is it morally acceptable from an intergenerational equity point of view.”
….The researchers present four archetype scenarios that incorporate a broader range of potential mitigation options. These include:
Major reliance on carbon dioxide removal in the future, the current archetype of many existing scenarios for achieving the 2°C or more stringent 1.5°C target.
Rapid decarbonization starting immediately, and halving every decade as proposed in a recent Science commentary coauthored by IIASA researchers.
Earlier implementation of carbon dioxide removal technologies, and phasing out by the end of the century
Consistent implementation of carbon dioxide removal from now until the end of the century.
Under all these scenarios, current country commitments under the Paris Agreement would not be sufficient to achieve the required cuts, the researchers say…
….IIASA researcher Fabian Wagner, another study coauthor adds, “In this paper we have shown that negative emission technologies may not only be an asset but also an economic burden if not deployed with care. We as scientists need to be careful when we communicate to policymakers about how realistic different scenarios might be. When we present scenarios that require the world to convert an amount of land equivalent to all today’s cropland to energy plantations, alarm bells should go off.”
Michael Obersteiner, Johannes Bednar, Fabian Wagner, Thomas Gasser, Philippe Ciais, Nicklas Forsell, Stefan Frank, Petr Havlik, Hugo Valin, Ivan A. Janssens, Josep Peñuelas, Guido Schmidt-Traub. How to spend a dwindling greenhouse gas budget. Nature Climate Change, 2018; 8 (1): 7 DOI: 10.1038/s41558-017-0045-1
New research predicts a significantly drier world if global warming reaches 2ºC. Over a quarter of the world’s land could become significantly drier and the change would cause an increased threat of drought and wildfires.
The change would cause an increased threat of drought and wildfires.
But limiting global warming to under 1.5C would dramatically reduce the fraction of the Earth’s surface that undergoes such changes. Areas which would most benefit from keeping warming below 1.5ºC include Central America, Southern Europe, Southern Australia, parts of South East Asia, and Southern Africa.
…Dr Chang-Eui Park….one of the authors of the study, said: “Aridification is a serious threat because it can critically impact areas such as agriculture, water quality, and biodiversity. It can also lead to more droughts and wildfires — similar to those seen raging across California.
“Another way of thinking of the emergence of aridification is a shift to continuous moderate drought conditions, on top of which future year-to-year variability can cause more severe drought.
The climate change simulations that best capture current planetary conditions are also the ones that predict the most dire levels of human-driven warming, according to a statistical study released in the journal Nature on Wednesday.
The study, by Patrick Brown and Ken Caldeira of the Carnegie Institution for Science in Stanford, California, examined the high-powered climate change simulations, or models, that researchers use to project the future of the planet based on the physical equations that govern the behavior of the atmosphere and oceans….
….Lead study author Brown argued, though, that the results have a major real-world implication: They could mean the world can emit even less carbon dioxide than we thought if it wants to hold warming below the widely accepted target of 2 degrees Celsius (3.6 degrees Fahrenheit). This would mean shrinking the “carbon budget.”
The study “would imply that to stabilize temperature at 2 degrees Celsius, you’d have to have 15 percent less cumulative CO2 emissions,” he said.
The first main chapter deals with changes to the climate and focuses much attention on global temperatures. When most people think of climate change, they think of the global temperature – specifically the temperature of the air a few meters above the Earth surface. There are other (better) ways to measure climate change such as heat absorbed by the oceans, melting ice, sea level rise, or others. But the iconic measurement most people think of are these air temperatures, shown in the top frame of the figure below….
November 16, 2017 University of Exeter Read full ScienceDaily article here
Some impacts of global warming — such as sea level rise and coastal flooding — are already locked in and unavoidable, according to a major research project.
Global temperatures have already risen by around 1°C, and a further 0.5°C warming is expected. The full impacts of current warming have not yet been seen, since ice sheets and oceans take many decades to fully react to higher temperatures.
But more severe impacts can still be avoided if global greenhouse gas emissions are reduced.
More than 50 scientists from 16 institutions in 13 countries have worked on the HELIX project (High-End Climate Impacts and Extremes), which has just finished after four years. The project examined the possible effects of warming of 1.5°C, 2°C, 4°C and 6°C compared to pre-industrial levels.
Even with rapid cuts in global greenhouse gas emissions keeping warming below 2°C, sea levels could rise by 0.5m by the end of the 21st Century, particularly affecting small island states and low-lying countries. HELIX calculations suggest this could impact 2.5 million in Bangladesh….
I am writing Scientific Reticence and the Fate of Humanity in response to a query from the editor of Atmospheric Chemistry and Physics who handled Ice Melt, Sea Level Rise and Superstorms. That paper, together with Young People’s Burden makes the case for a low global warming target and the urgency of phasing out fossil fuel emissions. We argue that global warming of 2°C , or even 1.5°C, is dangerous, because these levels are far above Holocene temperatures and even warmer than best estimates for the Eemian, when sea level reached 6-9 meters (20-30 feet) higher than today. Earth’s history shows that sea level adjusts to changes in global temperature. We conclude that eventual sea level rise of several meters could be locked in, if rapid emission
reductions do not begin soon, and could occur within 50-150 years with the extraordinary climate forcing of continued “business-as-usual” fossil fuel emissions….