When we see records being broken and unprecedented events such as this, the onus is on those who deny any connection to climate change to prove their case. Global warming has fundamentally altered the background conditions that give rise to all weather. In the strictest sense, all weather is now connected to climate change. Kevin Trenberth
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Acclimatise, Climate Finance Advisors (CFA), and Four Twenty Seven have released a new guidance document to increase the climate resilience of large infrastructure investments. The “Lenders’ Guide for Considering Climate Risk in Infrastructure Investments” clearly breaks down the ways in which physical climate risks might affect key financial aspects of prospective infrastructure investments.
This guide provides a framework for questioning how revenues, costs, and assets can be linked to potential project vulnerability arising from climate hazards and draws attention to the potential opportunities emerging from resilience-oriented investments in infrastructure.
Ten sub-sectors, including airports, marine ports, gas and oil transport and storage, power transmission and distribution, wind-based power generation, data centers, telecommunications, commercial real estate, healthcare, and sports and entertainment, are analysed and illustrated with topical examples.
To learn more about this document, please visit our website and download the publication here.
“We have a new normal” thanks to climate change, explains leading reinsurer.
by Joe Romm, Climate Progress, January 4, 2018
HURRICANE HARVEY IMPACTS. CREDIT: GETTY IMAGES
It turns out 2017 was a uniquely disastrous year in more ways than one, evidenced by German reinsurer Munich Re’s recently released review of the year’s global catastrophes.
Led by massive, climate change-fueled hurricanes Harvey, Irma, and Maria, 2017’s natural disasters will cost insurers a record $135 billion. Adding in uninsured losses brings the total global damages to $330 billion, which is second only to 2011.
“We have a new normal,” Munich Re’s Ernst Rauch told Reuters. Rauch, who runs the group tracking climate change risks, pointed out that “2017 was not an outlier” in having more than $100 billion in insured losses (see chart below). “We must have on our radar the trend of new magnitudes,” Rauch said.
The big reinsurers like Munich Re make their money by insuring the companies that directly insure your property. Those smaller companies are often required by law to buy reinsurance because they lack the capital resources to pay out if there is a major disaster, like superstorm Harvey for instance.
Since the reinsurers must pay out billions and billions of dollars for such mega-disasters, they have a unique incentive to understand and predict trends in mega-disasters. That’s why companies like Munich Re and Swiss Re have been at the forefront of warning businesses and the public about the rise in extreme weather events due to climate change.
Indeed, back in September 2010, another year of stunning warming-driven extreme weather events, Munich Re issued a release noting it had analyzed its catastrophe database, “the most comprehensive of its kind in the world,” and concluded, “the only plausible explanation for the rise in weather-related catastrophes is climate change.”
Then in October 2012, the company released a massive 274-page report, “Severe weather in North America,” analyzing weather catastrophes and related losses since 1980 to understand trends and their causes, including man-made climate change.
Munich Re found that the number of weather-related loss disasters has been rising much faster in North America than anywhere else, and concluded, “Climate-driven changes are already evident over the last few decades for severe thunderstorms, for heavy precipitation and flash flooding, for hurricane activity, and for heatwave, drought and wildfire dynamics in parts of North America.”
Prof. Peter Höppe, who heads Munich Re’s Geo Risks Research unit, said at the time, “In all likelihood, we have to regard this finding as an initial climate-change footprint in our U.S. loss data from the last four decades.”
And last April, Munich Re published an article on “rapid attribution,” which explained that we can now rapidly determine how much intensity or frequency of some extreme weather events is affected by man-made climate change. Learning that, for instance, climate change has sharply increased the chances of individual extreme rain and flooding events – such as devastating August 2016 deluge and flooding of Baton Rouge, Louisiana – allows communities to do better planning and Munich Re to do better risk management.
The latest annual report amplifies the message that humans are changing the climate, boosting the intensity and frequency of extreme weather events, and that the longer we dawdle, the higher the costs we will incur. The only question is, is anyone listening?
Mesoscale convective system (MCS)-organized convective storms with a size of ~100 km have increased in frequency and intensity in the USA over the past 35 years1, causing fatalities and economic losses2. However, their poor representation in traditional climate models hampers the understanding of their change in the future3. Here, a North American-scale convection-permitting model which is able to realistically simulate MSCs4 is used to investigate their change by the end-of-century under RCP8.5 (ref. 5). A storm-tracking algorithm6 indicates that intense summertime MCS frequency will more than triple in North America. Furthermore, the combined effect of a 15–40% increase in maximum precipitation rates and a significant spreading of regions impacted by heavy precipitation results in up to 80% increases in the total MCS precipitation volume, focused in a 40-km radius around the storm center. These typically neglected increases substantially raise future flood risk. Current investments in long-lived infrastructures, such as flood protection and water management systems, need to take these changes into account to improve climate-adaptation practices.
by Floodlist News, November 28, 2017 Major clusters of summertime thunderstorms in North America will grow larger, more intense, and more frequent later this century in a changing climate, unleashing far more rain and posing a greater threat of flooding across wide areas, new research concludes. The study, by scientists at the National Center for Atmospheric Research (NCAR), builds on previous work showing that storms are becoming more intense as the atmosphere is warming. In addition to higher rainfall rates, the new research finds that the volume of rainfall from damaging storms known as mesoscale convective systems (MCSs) will increase by as much as 80% across the continent by the end of this century, deluging entire metropolitan areas or sizable portions of states.
“The combination of more intense rainfall and the spreading of heavy rainfall over larger areas means that we will face a higher flood risk than previously predicted,” said NCAR scientist Andreas Prein, the study’s lead author. “If a whole catchment area gets hammered by high rain rates, that creates a much more serious situation than a thunderstorm dropping intense rain over parts of the catchment.”
“This implies that the flood guidelines which are used in planning and building infrastructure are probably too conservative,” he added.
The research team drew on extensive computer modeling that realistically simulates MCSs and thunderstorms across North America to examine what will happen if emissions of greenhouse gases continue unabated.
The study will be published November 20, 2017, in the journal Nature Climate Change. It was funded by the National Science Foundation, which is NCAR’s sponsor, and by the U.S. Army Corps of Engineers.
Thunderstorms and other heavy rainfall events are estimated to cause more than $20 billion of economic losses annually in the United States, the study notes. Particularly damaging, and often deadly, are MSCs: clusters of thunderstorms that can extend for many dozens of miles and last for hours, producing flash floods, debris flows, landslides, high winds, and/or hail. The persistent storms over Houston in the wake of Hurricane Harvey were an example of an unusually powerful and long-lived MCS.
Storms have become more intense in recent decades, and a number of scientific studies have shown that this trend is likely to continue as temperatures continue to warm. The reason, in large part, is that the atmosphere can hold more water as it gets warmer, thereby generating heavier rain.
A study by Prein and co-authors last year used high-resolution computer simulations of current and future weather, finding that the number of summertime storms that produce extreme downpours could increase by five times across parts of the United States by the end of the century. In the new study, Prein and his co-authors focused on MCSs, which are responsible for much of the major summertime flooding east of the Continental Divide. They investigated not only how their rainfall intensity will change in future climates, but also how their size, movement, and rainfall volume may evolve.
Analyzing the same dataset of computer simulations and applying a special storm-tracking algorithm, they found that the number of severe MCSs in North America more than tripled by the end of the century. Moreover, maximum rainfall rates became 15-40% heavier, and intense rainfall reached farther from the storm’s center. As a result, severe MCSs increased throughout North America, particularly in the northeastern and mid-Atlantic states, as well as parts of Canada, where they are currently uncommon.
The research team also looked at the potential effect of particularly powerful MCSs on the densely populated Eastern Seaboard. They found, for example, that at the end of the century, intense MCSs over an area the size of New York City could drop 60% more rain than a severe present-day system. That amount is equivalent to adding six times the annual discharge of the Hudson River on top of a current extreme MCS in that area.
“This is a warning signal that says the floods of the future are likely to be much greater than what our current infrastructure is designed for,” Prein said. “If you have a slow-moving storm system that aligns over a densely populated area, the result can be devastating, as could be seen in the impact of Hurricane Harvey on Houston.”
Intensive Modeling
Advances in computer modeling and more powerful supercomputing facilities are enabling climate scientists to begin examining the potential influence of a changing climate on convective storms such as thunderstorms, building on previous studies that looked more generally at regional precipitation trends.
For the new study, Prein and his co-authors turned to a dataset created by running the NCAR-based Weather and Research Forecasting (WRF) model over North America at a resolution of 4 kilometers (about 2.5 miles). That is sufficiently fine-scale resolution to simulate MCSs. The intensive modeling, by NCAR scientists and study co-authors Roy Rasmussen, Changhai Liu, and Kyoko Ikeda, required a year to run on the Yellowstone system at the NCAR-Wyoming Supercomputing Center.
The team used an algorithm developed at NCAR to identify and track simulated MCSs. They compared simulations of the storms at the beginning of the century, from 2000 to 2013, with observations of actual MCSs during the same period, and showed that the modeled storms are statistically identical to real MCSs.
The scientists then used the dataset and algorithm to examine how MCSs may change by the end of the century in a climate that is approximately 5 degrees Celsius (9 degrees Fahrenheit) warmer than in the pre-industrial era — the temperature increase expected if greenhouse gas emissions continue unabated.
Climate change is upsetting rainfall patterns and the frequency of flooding in West Africa as it makes the region's Sahel storms three times likelier.
by Tim Radford, Climate News Network, May 7, 2017
LONDON – Climate change has already made a difference to life in the West African Sahel, the arid belt of land stretching from the Atlantic to the Red Sea which separates the Sahara desert from the African savanna. It has made catastrophic storms three times more frequent.
And, according to a new study in the journal Nature, Sahel storms are among the most powerful on the planet. In 2009, one vast downpour deposited 263 mm of rain over Ouagadougou, the capital of Burkina Faso, claiming 8 lives, flooding half the city and forcing 150,000 people out of their homes.
Researchers believe the pattern of thunderstorms known as mesoscale convective systems will increase in frequency as global temperatures rise, as a consequence of increasing levels of carbon dioxide in the atmosphere, in turn driven by worldwide use of fossil fuels as sources of energy.
Mesoscale convective systems are big, bad, and very cold columns of thunderous cloud: up to 16 km high, covering an area of 25,000 square kilometres, and with temperatures at the highest altitude as low as minus 40 °C.
Between 1986 and 2005, Burkina Faso registered floods at a rate of little more than one a year. In the 11 years between 2006 and 2016, it was hit by 55 flood events.
Repeated warnings
Climate scientists have been warning for three decades that global warming will be accompanied by an increase in “extreme” events: in particular drought, flood, heat wave, and tropical cyclone.
Global warming has already been observed in the Sahel, and the consequences have not necessarily been bad: overall, precipitation has increased, and farmers have benefited, although in a dryland region south of the Sahara where people have endured a 2,000-year history of periodic drought, famine remains a constant hazard.
And now, so do massive downpours of rain: the Sahel storms. British and French scientists examined 35 years of satellite data and the rain gauges in the region to identify a rise in extreme daily rainfall totals. They found 85% of extreme rainfall cases coincided with satellite records of a passing mesoscale convection system.
They also examined the pattern of temperatures over the region and found that although the annual average temperatures have risen, the so-called “wet season” temperatures have remained steady. That is, locally warmer conditions alone have not brought more rainfall.
“Global warming is expected to produce more intense storms, but we were shocked to see the speed of changes taking place in this region of Africa”
Instead, they blame man-made global warming which has changed wind and rain conditions, and this will go on strengthening during this century, “suggesting the Sahel will experience particularly marked increases in extreme rain,” they conclude.
“Global warming is expected to produce more intense storms, but we were shocked to see the speed of changes taking place in this region of Africa,” said Christopher Taylor, a meteorologist at the UK’s Centre for Ecology and Hydrology, who led the study.
His co-author Douglas Parker, professor of meteorology at the University of Leeds in the UK, said: “African storms are highly organised meteorological engines, whose currents extract water from the air to produce torrential rain.
Cameron Wake, professor of climatology and glaciology at the University of New Hampshire, said Portsmouth homeowners in low-lying areas in the South End consider selling their houses now. Photo by Ioanna Raptis/Seacoastonline
PORTSMOUTH — People who live in a low-lying area of the city like the South End should consider selling their house — “and I’m not kidding,” said Cameron Wake, University of New Hampshire professor of climatology and glaciology.
If there is a big coastal storm like Hurricane Sandy, “those houses are at risk of flooding” today. And it won’t get any better in the years to come, as sea levels inevitably continue to rise.
“My recommendation is why deal with the headache? Sell now while you can still get money out of the home,” he said.
As for Hampton Beach, he said, the town’s move toward making the beach a 5-star resort area is misguided at best. “Hampton Beach is so at risk, so vulnerable, so exposed” that it makes no economic sense to continue on that path.
Wake spoke to the Herald editorial board Wednesday, in advance of his talk next week at 3S Artspace in Portsmouth. He said sea level rise from climate change is occurring now and its trajectory is inevitable. The question is how quickly will we curtail human activities that contribute to global warming?
Will carbon emissions continue unabated at current levels — in which case sea levels could rise as much as 6 feet in the next 80 years, leaving Hampton Beach, Strawbery Banke Museum, Portsmouth Middle School and South Mill Pond homes in Portsmouth under water? “I don’t mean to be hyperbolic here, but that’s the picture,” said Wake.
Or will there be a serious and immediate commitment to reducing carbon emissions by systemically investing in renewable energy sources, weaning off high carbon use, implementing energy efficiency measures and instituting a carbon tax? In the most optimistic case, then, sea levels would rise 2 feet over the next 80 years, “something we can adapt to, something we can survive.”
Wake sees reasons for optimism amid concerns that the planet could be facing “a whole suite of nasty surprises” in the future — including the possibility of more accelerated melting of the Greenland and West Antarctic ice sheets than had previously been anticipated. Former NASA scientist James Hansen in a study released this week predicted even if the Earth warms by a modest 3.5 degrees Fahrenheit by 2100 — as agreed to by the nations of the world in Paris last December — it will be too warm to stop the sheets from melting. That would cause sea levels to rise quickly and precipitously, the study argues.
“The conversation we’re not having is the conversation Jim Hansen wants us to have,” said Wake. “We had to get over the denial, and we’ve done that. Now we need to take a hard look at where we go from here.”
Wake was asked what number he would assign the world today, if zero was the worst carbon pollution possible and 10 was the perfect climate world.
“I think we’re at about a 1," he said. "The developed world needs to be carbon neutral by 2050. We need to get to 10 really quickly,” he said, and then help developing countries reach that goal in the decades to follow. “But when you look at the rate of change today, we’re headed in the right direction.”
That’s where the optimism comes in, he said. It’s become clear in recent years that a solution to global warming is becoming cost effective, he said. The cost of wind and solar has come down, for instance.
“We can see a pathway to a clean energy revolution that wasn’t there before. The tipping point is where capital, interest and technology all meet. I’m optimistic because solutions line up with profit motives,” he told the Herald last December.
He likened it to the Internet. Early on, comparatively few people used the Internet, but then it reached the same critical mass “and took off exponentially. That same exponential curve is happening now” with renewable energy.
In order for this trajectory to continue, people need to incorporate changes in their personal lives, and begin demanding their elected leaders from town hall to Congress deal with this issue. “Once politicians hear from many people, I think they will start to get much more serious.”
While there are many challenges ahead, he said, he said “it’s not too late. There is an amount of climate change we are going to have to adapt to. We have already committed to a warmer world. But if we can act now, in the next decade, and the developing world in the next two or three decades, I do think we can salvage this.”
by Kevin Trenberth, The Conversation, January 4, 2016
A major El Niño is under way now. It already has substantially influenced weather patterns around the globe, but could have even bigger impacts this winter. There have been only two “super” El Niños until now: in 1982-83 and 1997-98. We are now experiencing a third “super” El Niño.
Every El Niño cycle is different. The effects from this year’s already include a record number of hurricanes/typhoons in the Pacific and intense wildfires in Indonesia.
In the United States over the next several months, El Niño is expected to cause heavy rains across the South, with the potential for coastal flooding in California, along with relatively mild and dry weather in the northern states. Global climate change, which, along with the El Niño, is making 2015 the warmest year on record, is likely to amplify these impacts.
What is El Niño?
El Niños are not uncommon. Every three to seven years or so, the surface waters of the tropical Pacific Ocean become extremely warm from the International Dateline to the west coast of South America. This process causes changes in the local and regional ecology, and is clearly linked with abnormal global climate patterns.
The Oceanic Niño Index (ONI) shows warm (red) and cold (blue) phases of abnormal sea surface temperatures in the tropical Pacific Ocean.NCAR,Author provided
Historically “El Niño” referred to the appearance of unusually warm water off the coast of Peru near Christmastime (Niño is Spanish and refers to “the boy Christ child”). Today it describes broader changes that occur across the Pacific basin.
Oceanic and atmospheric conditions in the tropical Pacific fluctuate somewhat irregularly between warm El Niño phases and cold phases in which surface waters cool across the tropical Pacific. These cooling events are called “La Niña” (“the girl” in Spanish). The most intense phase of each event typically lasts about a year.
El Niño is linked to major changes in the atmosphere known as the Southern Oscillation(SO). Scientists call the whole phenomenon the El Niño–Southern Oscillation (ENSO). During El Niño, higher-than-normal surface air pressures develop over Australia, Indonesia, Southeast Asia and the Philippines, producing drier conditions or even droughts. Dry conditions also prevail in Hawaii, parts of Africa, and northeastern Brazil and Colombia.
Lower pressures develop over the central and eastern Pacific, along the west coast of South America, parts of South America near Uruguay and southern parts of the United States in winter, often producing heavy rains and flooding. Regions that are typically dry during El Niño events tend to become excessively wet during La Nina events, and vice versa.
Flooding in Clear Lake, California, March 1 1998, during the 1997-1998 ‘super’ El Niño event.Dave Gatley/FEMA
Why does El Niño happen?
ENSO is a natural phenomenon arising from coupled interactions between the atmosphere and the ocean in the tropical Pacific Ocean. Changing sea surface temperatures alter rainfall and surface winds, which in turn alter ocean currents and sea surface temperatures. These interactions produce a positive feedback loop, in which each change tends to promote further changes. There is good evidence from core samples taken from coral reefs and glacial ice in the Andes that ENSO has been going on for millennia.
During El Niño, trade winds that typically blow from east to west across the Pacific weaken. Sea level falls in the western Pacific and rises in the east by as much as a foot as warm waters surge eastward along the equator. The resulting increase in sea temperatures warms and moistens the overlying air. This triggers a process called convection: the warm, moist air rises into the atmosphere, altering normal rainfall patterns and associated releases of heat.
Somewhat like a rock sitting in a stream of water, this unusual heating sets up teleconnections: continental-scale waves in the atmosphere that extend into the midlatitudes in winter. These waves alter winds and change the jet stream and storm tracks, creating persistent weather patterns. The changes in sea surface temperatures associated with El Niño reach their most extreme point during winter in the Northern Hemisphere, so we see the biggest effects then.
The 2015-16 El Niño event
Because Pacific surface waters are much warmer and atmospheric circulation patterns throughout the tropics are altered, fewer tropical storms and hurricanes than normal occur in the tropical Atlantic during El Niño. But there is much more activity than usual in the Pacific. Super Typhoon Pam, which ripped through Vanuatu in March 2015 causing enormous damage, was fueled by warm waters from El Niño.
During the northern Pacific hurricane season in the summer and fall of 2015, 25 category 4 and 5hurricanes/typhoons developed, a record as compared to the previous record of 18. Changed weather patterns resulted in lack of rain and thus strong drought and wildfires in Indonesia that have degraded air quality over hundreds of miles.
El Niño has recently affected the Indian Ocean. The Bay of Bengal is already exceptionally warm, which has led to record-breaking rains and widespread flooding and devastation in Chennai, southeastern India, with 47 inches of rain in November and a further 11 inches of rain in the first week of December. This Indian Ocean activity may disrupt the expected development of El Niño patterns around the world. El Niño-related heavy rains have also recently (December 2015) occurred in the Americas: in Paraguay and surrounding areas, and in Missouri. The latter has led to considerable flooding of the Mississippi, reminiscent of the El Niño-related Mississippi flooding in 1993.
Sea surface temperature anomalies from El Niño tend to peak in December, and this year the changes may already have peaked in late November. However, the seasonal cycle further increases total sea surface temperatures, so the biggest impacts on the atmosphere often occur in the following February or March. This El Niño began in 2014, but stalled, and then regrouped in 2015. Every El Niño event is different, but according to NOAA’s latest monthly outlook, El Niño conditions are expected to peak during the winter of 2015-16 before gradually weakening through spring 2016 and terminating by late spring or early summer 2016.
Sea surface temperature anomalies through early December during the ‘super’ El Niño in 1997 and the current El Niño.
During the coming months, climate scientists expect that El Niño will pull the east Pacific Northern Hemisphere jet stream and its associated storm track southward. Normally these storms veer to the north toward the Gulf of Alaska or enter North America near British Columbia and Washington, where they often link up with cold Arctic and Canadian air masses and bring them down into the United States. Instead, with the jet stream following an altered path, the northern states are likely to experience relatively mild and drier-than-normal weather. Storms tracking across the continent further to the south will likely create wet conditions in California and across the South as far east as Florida.
Each El Niño event has its own character. In the El Niño winters of 1992–93, 1994–95, 1997–98 and 2004-05, southern California was battered by storms and experienced flooding and coastal erosion. However, in more modest El Niños, including the 1986–87 and 1987–88 winters, California was more at risk from droughts. Given the scale of this year’s El Niño, Californians should prepare for heavy rains, possible flooding and heavy coastal erosion, driven by the combined effects of higher sea levels (driven by climate change and El Niño effects) and storm surges.
El Niño and global warming
All of the impacts of El Niño are exacerbated by global warming. Globally, temperatures for 2015 are the highest on record, in part because of the El Niño event. Global warming sets the background and El Niño determines regional weather patterns. When they work together in the same direction, they have the biggest effects and records are broken.
Changes associated with El Niño, including droughts, floods, heat waves and other changes, take a heavy toll in many parts of the world. They can severely disrupt agriculture, fisheries, the environment, health, energy demand and air quality, and increase the risks of wildfires. The risk of adverse effects and more frequent extremes or even records occurring is heightened by global climate change from human activities.
By better understanding El Niño, predictions and alerts can allow us to be prepared for possible unusual effects, but we can and should act to slow down climate change.
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