Category: Climate Change Impacts

2017: The United States’ Year of Billion Dollar Weather and Climate Disasters

2017: The United States’ Year of Billion Dollar Weather and Climate Disasters

By Georgina Wade

It turns out that 2017 was uniquely disastrous to the United States in more ways than one with the National Oceanic and Atmospheric Administration (NOAA) attributing a cumulative damage amount of $306.2 billion to 16 separate disaster events, a record previously held in 2005.

Hurricanes Harvey, Irma and Maria combined with 2017’s extreme wildfires make up four of the 16 weather and climate disasters with losses exceeding $1 billion each. Overall, these events resulted in the deaths of 362 people and had significant economic effects on the areas impacted.

Source: NOAA National Centers for Environmental Information (NCEI)

Since 1980, the U.S. has sustained 219 billion-dollar climate-related disasters with cumulative costs exceeding $1.5 trillion dollars. From 1980-2016, the annual average number of billion-dollar events was 5.8 whereas the most recent five years (2013-2017) saw an annual average of 11.6 events.

With $135 billion expected in insured losses, 2017 is also a costly year for the insurance industry, giving reinsurance companies such as MunichRe a primary role in helping people and communities rebuild in the wake of natural catastrophes.

Source: Munich Re NatCatSERVICE

Acting as an insurer for insurance companies, MunichRe utilises NOAA’s National Centers for Environmental Information (NCEI) to understand the probability of these natural disasters and sell premiums to insurance companies in exchange for coverage.

As insurance companies are often required by law to buy reinsurance because they lack the capital resources to pay out if there is a major disaster, companies like MunichRe have a unique incentive to understand and predict these trends.

Additionally, this understanding has resulted in reinsurers being at the forefront of warning businesses and the public about the rise in extreme weather events due to climate change.

A MunichRe release in September 2010 noted it had analysed 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.

NOAA researcher Adam B. Smith agrees, citing climate change as a primary culprit in the frequency of these severe weather and climate events.

“Climate change is playing an increasing role in the increasing frequency of some types of extreme weather that lead to billion-dollar disasters,” Smith wrote in a blog post. “Most notably the rise in vulnerability to drought, lengthening wildfire seasons and the potential for extremely heavy rainfall and inland flooding events are most acutely related to the influence of climate change.”

Cover photo by Marcus Kauffman on Unsplash: Big Fall Creek Road, Lowell, United States, during the Jones Fire in August 2017.

Learn more about the role of NOAA’s NCEI data by clicking here and watching our video below:

2017: the year in extreme weather

2017: the year in extreme weather

By Andrew King, University of Melbourne

Overall 2017 will be the warmest non-El Niño year on record globally, and over the past 12 months we have seen plenty of extreme weather, both here in Australia and across the world. Here I’ll round up some of this year’s wild weather, and look forward to 2018 to see what’s around the corner.

Drought and flooding rains… again

It feels as if Australia has had all manner of extreme weather events in 2017. We had severe heat at both the start and end of the year. Casting our minds back to last summer, both Sydney and Brisbane experienced their hottest summers on record, while parts of inland New South Wales and Queensland endured extended periods of very high temperatures.

More recently Australia had an unusually dry June and its warmest winter daytime temperatures on record. The record winter warmth was made substantially more likely by human-caused climate change.

The end of the year brought more than its fair share of extreme weather, especially in the southeast. Tasmania had by far its warmest November on record, beating the previous statewide record by more than half a degree. Melbourne had a topsy-turvy November with temperatures not hitting the 20℃ mark until the 9th, but a record 12 days above 30℃ after that.

November was rounded off by warnings for very severe weather that was forecast to strike Victoria. Melbourne missed the worst of the rains, although it still had a very wet weekend on December 2-3. Meanwhile, northern parts of the state were deluged, with many places recording two or three times the December average rainfall in just a couple of days.

Hurricane after hurricane after hurricane…

Elsewhere in the world there was plenty more headline-worthy weather. The Atlantic Ocean had a particularly active hurricane season, with several intense systems. Hurricane Harvey struck Texas and its slow trajectory resulted in record-breaking rainfall over Houston and neighbouring areas.

Then Hurricanes Irma and Maria, both of which reached the strongest Category 5 status, brought severe weather to the Caribbean and southeastern United States just a couple of weeks apart. Island nations and territories in the region are still recovering from the devastation.

Around the same time, the Indian subcontinent experienced a particularly wet monsoon season. Flooding in India, Pakistan, Bangladesh, and Nepal killed more than 1,000 people and affected tens of millions more. Other parts of the world experienced their own severe weather events. Whether it was summer heat in Europe or wildfires in California, 2017 dished up plenty of extremes.

In many cases, especially for heat extremes, we can rapidly identify a human influence and show that climate change is increasing the frequency and intensity of such events. For other weather types, like the very active hurricane season and other extreme rain or drought events, it is harder (but not always impossible) to work out whether it bears the fingerprint of climate change.

What’s in store for 2018?

The main problem when trying to offer an outlook is that extreme weather is hard to predict, even on the scale of days or weeks in advance, let alone months.

For Australia, with a weak La Niña in the Pacific, there are few clear indications of what the rest of the summer’s weather will bring. There is a suggestion that we can expect a slightly wetter than average start to the year in parts of the southeast, along with warmer than average conditions for Victoria and Tasmania. Beyond that it is anyone’s guess.The La Niña is also likely to mean that 2018 won’t be a record hot year for the globe. But it’s a safe bet that despite the La Niña, 2018 will still end up among the warmest years on record, alongside every other year this century. Rising global average temperatures, along with our understanding of the effect of greenhouse gas emissions, are one of our clearest lines of evidence for human-caused climate change.

The ConversationSo it’s hard to say much about what extreme weather we’ll experience in 2018, other than to say that there’s likely to be plenty more weather news to wrap up in a year’s time.

Andrew King, Climate Extremes Research Fellow, University of Melbourne. This article was originally published on The Conversation. Read the original article.

Cover animation by NOAA (public domain): A Rainbow Infrared graphic of Hurricane Maria from 05:45 UTC to 12:45 UTC 20 September 2017 from sensors on the GOES Floater satellite.
Texas faces more Harvey-sized hurricanes

Texas faces more Harvey-sized hurricanes

By Tim Radford

Hurricane Harvey caused devastation when it hit Houston. The likelihood of further  Harvey-sized hurricanes hitting Texas is rising. The probability that some city in the US state of Texas will be hit again by Harvey-sized hurricanes, rainstorms that will dump half a metre of water in a short space of time, has increased sixfold in this century and will have increased 18-fold by 2100, thanks to climate change driven by global warming.

In the late summer of 2017, Hurricane Harvey dropped 65 cms of water on the city of Houston in Texas. It was the start of the largest natural disaster in the US since Hurricane Katrina pounded New Orleans in 2005. Harvey claimed an estimated 70 lives, and created more than $150 billion in damage.

Kerry Emanuel, a meteorologist and professor of atmospheric science at Massachusetts Institute of Technology, asked a simple question: how likely is it that hurricane-induced flooding of such magnitude could happen again?

He reports in the Proceedings of the National Academy of Sciences that he looked again at the probabilities. Since 1899, only 11 US hurricanes have brought with them rainfalls that measured more than 65 cms. Until Harvey, the most recent had been a hurricane called Patricia which dumped more than 50 cms in some parts of Texas.

For Texas alone, from 1981 to 2000, the chance of an event on the scale of Harvey or Patricia was 1%: that is, one chance in a hundred during any one year, with a high likelihood of such an event once every 100 years.

“We are seeing for Texas an event whose annual probability was 1% at the end of last century, and it might be 18% by the end of this century. That’s a huge increase”

Harvey would once have counted as the storm of the century, and the chance of it hitting Houston made it an even more improbable event. Statistically, such a thing should happen once in 2,000 years.

But the past, Professor Emanuel argues, is no longer a good guide to the future. “When you take a very, very rare, extreme rainfall event like Hurricane Harvey, and you shift the distribution of rain toward heavier amounts because of climate change, you get really big changes in the probability of those rare events,” he said. “People have to understand that damage is usually caused by extreme events.”

He is not the only researcher to have looked at the statistics with alarm. More than one study has found that the Atlantic coast of the US could face harder and more frequent battering as global temperatures creep up in response to ever-increasing use of fossil fuels that leave ever-growing ratios of the greenhouse gas carbon dioxide in the atmosphere.

One group has warned that coastal storms and floods could create new millions of US climate refugees. The problem is not uniquely an American one: by the century’s end, coastal flooding could be costing the nations of the world $100 trillion a year, as sea levels rise and extreme events such as tropical cyclones and storm surges become more intense, and more frequent.

Odds on calamity

Some studies have concentrated on conditions for particular coastal cities such as Charleston or Seattle, where the once-in-500-year floods could in the next century happen 273 times more often.

Studies like these may sound alarmist: in fact, they have a simple, practical purpose. City authorities need to know if the odds of calamity are on the increase.

“Suppose you’re the mayor of Houston, and you’ve just had a terrible disaster that cost you an unbelievable fortune, and you’re going to try over the next few years to put things back in order in your city. Should you be putting in a more advanced storm-sewer system that may cost billions of dollars, or not?

“The answer to that question depends upon whether you think Harvey was a one-off – very unlikely to happen any time in the next 100 years – or whether it may be more common than you thought,” Professor Emanuel said.

“We are seeing for Texas an event whose annual probability was 1% at the end of last century, and it might be 18% by the end of this century. That’s a huge increase in the probability of that event. So, people had better plan for that.”

This article was originally published on Climate News Network and is shared under a Creative Commons license. Read the original article by clicking here.

Cover photo by US Department of Defense (public domain): Army Sgt. Daniel Peters speaks with a family after assisting a local to safety in Orange, Texas, Sept. 3, 2017.
Study shows Hurricane Harvey’s record-shattering rainfall has climate change’s fingerprints all over it

Study shows Hurricane Harvey’s record-shattering rainfall has climate change’s fingerprints all over it

By Elisa Jiménez Alonso

Yesterday at the 2017 American Geophysical Union (AGU) Fall Meeting, researchers presented evidence from two separate studies that human-induced climate change increased the amount and intensity of Hurricane Harvey’s unprecedented rainfall.

Harvey made landfall in southern Texas on 25 August and dumped over 1,000mm (40 in) of rain in affected areas, with peak accumulations of 1,539mm (>60 in). It was the wettest tropical cyclone on record in the United States and caused catastrophic flooding that displaced over 30,000 people.

Now, two studies attribute the record-shattering rainfall of the hurricane to climate change. One study, which has been accepted for publication in the a GAU journal, finds Harvey’s rainfall total potentially increased by at least 19% and up to 38% compared to totals in the mid-20th century. Another study, published yesterday in the journal Environmental Research Letters, finds the record rainfall over Houston was made three times more likely and 15% more intense than similar storms in the early 1900s.

Researcher Michael Wehner of Lawrence Berkeley National Laboratory in Berkeley, California, a co-author of one of the studies, said “It is not news that climate change affects extreme precipitation, but our results indicate that the amount is larger than expected.”

The research confirms that heavy rainfall events across the Gulf of Mexico are increasing due to climate change. As warmer air carries more moisture and warming ocean surface temperatures intensify hurricanes, the region will have to ramp up its adaptation efforts in order to protect itself.

Cover photo by U.S. Air National Guard photo by Staff Sgt. Daniel J. Martinez (public domain): Members of the South Carolina’s Helicopter Aquatic Rescue Team (SC-HART) perform rescue operations in Port Arthur, Texas, August 31, 2017.
Hold on to your Christmas trees – climate impacts on the season’s favourite plant

Hold on to your Christmas trees – climate impacts on the season’s favourite plant

By Elisa Jiménez Alonso

Christmas trees, most commonly firs, pines or spruces, are a beloved staple during the holiday season. Behind all the fragrant green needles, colourful baubles and sparkling fairy lights lies a billion-dollar industry that produces tens of millions of live Christmas trees each year. The demand in Europe alone reaches about 50 million every year and in the US trees were sold at a retail value of over $2 billion in 2016. Due to climate change this massive industry is now facing some serious challenges from pests to frost.

Ironically, as our globe warms, trees are getting cold feet. In Scandinavia, Norwegian spruces are missing the insulating blanket of snow that helps protects their roots from sub-zero temperatures penetrating the soil. The frozen soil takes longer to thaw in spring, which in turn can stunt the trees’ growth and affect its overall health. Several snow-scarce years in a row can significantly impact production. In 2010, a tree shortage followed very harsh winters in Europe and led to a 25%-price hike – Christmas tree demand outstripped supply by 70 million trees.

Warmer temperatures also work in favour of Christmas trees’ biggest nemeses: pests. In Canada, the Balsam twig aphid loves sucking sap out of the popular Balsam and Fraser firs. While it gorges on the sap, the insect secretes a substance that makes the trees’ needles swell and curl. As the infestation increases, trees grow less needles and they start experiencing stunted growth. Southern Québec has seen a temperature increase between 0.8 °C and 1.6 °C since the 1960s and at current emission rates, temperatures could increase up to 4.6 °C above average in the 21st century.

As climate change progresses, Christmas tree producers will have to start thinking about ways to adapt their business to changing conditions. Solutions can range from moving production areas to higher altitudes for better weather conditions to diversifying the tree species in order to discourage pests from spreading. Given the long cycles tree farms go through, early adaptation measures are very important to ensure the businesses’ bottom line – and to save a beloved holiday tradition.

Photo by Diogo Palhais on Unsplash
How will climate change affect Arctic caribou and reindeer?

How will climate change affect Arctic caribou and reindeer?

By Conor Mallory, University of Alberta

This spring, I spent close to two weeks flying over central Nunavut, peering out the window of a small plane at the rolling tundra below, looking for and counting caribou to monitor their numbers.

The Qamanirjuaq barren-ground herd were arriving on their tundra calving grounds to give birth after migrating from winter ranges in the boreal forest. At times caribou dotted the landscape all the way to the horizon.

The terrain here is relatively pristine. There are few communities or developments. Due to the remoteness of the herd’s habitat, it is, in some ways, hard to imagine that human activities — whether climate change or industrial disturbance — could ever be of much concern to them.

And yet, we know that human activity and disturbance provide the most imminent threat to the persistence of many caribou and reindeer populations. (Reindeer and caribou are the same species, Rangifer tarandus, but have different English names in North America and Eurasia. Of course, the species has many names in different languages across the world, such as tuktu in Inuktitut.)

A complicated problem

Just how this iconic Arctic species will be affected in a warming climate remains unclear. Current predictions suggest that the climate will continue to change for decades into the future, regardless of the mitigation actions we take.

Caribou and reindeer have tremendous socioeconomic value in the north, and if we want to maintain sustainable caribou harvesting and husbandry in the future, we must understand how they will respond to environmental change.

My colleagues and I reviewed hundreds of scientific papers that studied caribou and reindeer from Alaska to Nunavut to Russia. By the end, we produced a complete picture of how climate change may affect the caribou and reindeer species, based on current knowledge.

We found that it’s challenging to make general predictions. The species has a circumpolar distribution and inhabits a variety of ecosystems, both similar and distinct. How different populations will respond to varying effects of climate change in this diverse range of systems is complex.

Summer effects

In many regions, climate change is causing longer and warmer summers. In the context of caribou, which live in colder regions, this typically means longer growing seasons and better access to nutritious plants throughout the summer months.

But plants are not the only part of the ecosystem affected by longer and warmer summers. Parasitic flies, particularly warble flies and botflies, torment caribou during the summer months. These insects aren’t just looking for blood like mosquitoes and black flies — they’re trying to lay their eggs on a caribou’s skin or in its nose.

As you can likely imagine, caribou want no part of this. They will spend hours running to escape these parasites, which means they spend less time feeding.

For a given region or herd, will increased plant growth or increase insect harassment have more of an effect on caribou?

We’re already seeing some of these effects play out. In Svalbard, Norway, warmer summers have been generally positive for caribou, as better plant growth has led to heavier animals in the fall. But in Arctic North America, more green growth has been associated with declines in caribou populations, possibly due to the northward expansion of less nutritious shrubs.

Research has shown that insects have been trouble for caribou in Arctic Finland. There, warmer weather brought more insects that harassed caribou calves, which led to less weight gain and more calf deaths.

Winter effects

Winter warming produces similarly complex effects. Climate change is predicted to increase the frequency of winter icing. Icing is usually caused by rain-on-snow or thaw-freeze events, and presents a real problem for caribou.

During the winter caribou dig in the snow to get to food underneath. Icing events trap food beneath an impenetrable layer of ice. These events have led to mass starvation of Arctic caribou and reindeer in the past.

On the other hand, longer autumns and earlier springs shorten the winter period of food scarcity. This should benefit caribou, but the net effect will depend on the balance of these changes in a given region.

These are just some of the wide-ranging potential implications of climate change for Arctic caribou and reindeer. They may also shift their ranges northward and alter their migratory behaviour in response to climate change, or begin sharing their lands with new or increased competitor species such as moose and white-tailed deer.

Importance of caribou and reindeer

Caribou and reindeer provide incredible value throughout the circumpolar world. In ecological terms, they are the most abundant large terrestrial herbivore. They have important grazing effects on plant communities and support predator populations.

The ecological importance of caribou means that changes to caribou and reindeer populations affect many other organisms, including wolves, Arctic shrubs and lichens.

They also have huge socioeconomic value. One report conservatively suggests that three herds in northern Canada provide the equivalent of $20 million dollars annually in food alone. Semi-domesticated reindeer similarly contribute huge value to those who herd them, including the Saami people of Finland, Russia, Norway and Sweden.

If there is a silver lining to this, it’s that we know caribou and reindeer live in a wide variety of environments and ecosystems — and this may provide them with some resilience.

But we don’t know if their ability to adapt is sufficiently agile to respond to the ongoing rapid environmental change in the north.

The ConversationScientists like myself need to work together with wildlife managers and harvesters to unravel the complexity of responses to environmental change. This information will be key to making decisions about caribou going forward.

Conor Mallory, PhD Student, University of Alberta. This article was originally published on The Conversation. Read the original article.

Cover photo by Christopher Michel (CC BY 2.0): Svalbard reindeer.
Shifting storms under climate change could bring wilder winters to the UK

Shifting storms under climate change could bring wilder winters to the UK

By Daisy Dunne

The UK could face harsher and more frequent winter storms if global greenhouse gas emissions aren’t curbed, a new study says.

The research uses modelling to investigate how rising global temperatures could change the movements of mid-latitude storms by the end of the century. These storms form outside of the tropics and are ferried across the Atlantic towards the UK along pathways known as “storm tracks”.

In a warmer world, these storm tracks are expected to shift to be closer towards the poles, the author tells Carbon Brief.

This means that mid-latitude storms could travel further before reaching their maximum intensity and, as a result, countries further from the equator, including the UK and the US, could face more frequent and more intense storms during winter months.

Shifting storms

Much of the UK’s more tempestuous winter weather is caused by storms blowing in from the Atlantic Ocean. The storms form in the mid-latitudes where warm air moving up from the tropics meets cold air coming down from the Arctic.

These storms are called “extratropical” because they form outside of the tropics, and they’re often referred to as “cyclones” because the storm weather system rotates anticlockwise. (However, they shouldn’t be confused with tropical cyclones that form in the tropics and can spin up to become hurricanes.)

Similar storms affect other mid-latitude countries in both the northern and southern hemisphere.

Previous studies have shown that, as temperatures and sea levels rise, extratropical storms may be able to form further from the equator, which could make it easier for them to spread polewards towards Europe and parts of North America.

However, the new Nature Geoscience study finds that climate change will not only influence the “birthplace” of extratropical storms, but will also provide them with more “fuel”, allowing them to travel further towards the poles, explains lead author Dr Talia Tamarin-Brodsky, a researcher from the University of Reading. She tells Carbon Brief:

“Most previous studies indicated that the regions of maximum storm activity shift poleward under climate change. However, most of these arguments involved changes in the latitude of where these midlatitude storms are ‘born’.

“Our study highlighted another aspect of the shift – we showed that the storms are not only generated more poleward, but they actually also travel larger distances. This means that the storms reach their maximum intensity at higher latitudes in a warmer climate.”

Using a set of 20 global climate models, the researchers simulated future changes in the behaviour of storms under a scenario where greenhouse gas emissions aren’t curbed (known as “RCP8.5”).

The researchers tracked both the frequency and movements of artificial storms forming above mid-latitude regions between the years 2080 and 2099. Tamarin-Brodsky explains:

“What these models show very robustly, as was shown by others in previous studies, is that the latitudinal position of the storm tracks shifts poleward. The ‘storm tracks’ are those regions in midlatitudes where storm mainly pass and are mainly active.”

The models also reveal that extratropical storms are likely to travel further polewards before reaching their maximum intensity, Tamarin-Brodsky says.

You can see this in the maps below, which show the historical locations (top left map) and starting points (top right) of extratropical storms tracks (for 1980-99). The red and orange shading shows where most storm tracks are found. You can see, for example, the density of storm tracks across the Pacific and Atlantic oceans.

The lower maps show the changes expected under RCP8.5 by 2080-99. Yellow and red indicates where the storm tracks are projected to shift to, and the blue shading indicates the move away from lower latitudes.

A comparison of storm track density (a) and birthplace (b) in the northern hemisphere from 1980 to 1999 to a projected storm track density (c) and birthplace (d) in 2080 to 2099 under RCP8.5. Yellow and red indicates a shift to higher latitudes, whereas light and dark blue shows a shift away from lower latitudes. Source: Tamarin-Brodsky & Kaspi (2017)

Changing winds

Climate change is expected to influence two physical processes that are key to the formation and movement of extratropical storms, Tamarin-Brodsky says.

The first of these processes involves the winds in the upper atmosphere that are necessary for storms to grow and travel. These winds are likely to become stronger as temperatures rise, the models suggest. Tamarin-Brodsky says:

“The second process is related to latent heat release. The hotter air in a warmer climate will contain more water vapour, and thus more heat will be released when the vapour condenses into drops.”

“The hottest, wettest air is circulating up the eastern flank of the storm – to the northern side – and releasing latent heat there. This process pushes the storm northward (or southward in the southern hemisphere), and this effect will also be stronger in a warmer climate.”

These changes are likely to most strongly affect regions that are close to the northeastern ocean boundaries, such as the US west coast and the UK. This is because extratropical storms generally form to the east of land masses and move westwards, gaining intensity as they go, explains Tamarin-Brodsky:

“In the Northern Hemisphere, midlatitude storms are usually generated over the oceans close to the east side of the continents, such as to the east of Japan and off the eastern coast of the United States, and generally travel eastward and somewhat poleward along similar paths.”

In the UK and the US, these physical changes could lead to more frequent and more severe storms, she adds:

“[The models] showed that both the number and the wind speed of cyclones increase in the UK and the British Isles.”

The research also hints at more stormy weather in northeastern parts of the US and Canada, says Prof Dan Chavas, a researcher in atmospheric sciences at Purdue University. He tells Carbon Brief:

“The methodology is nice because they are actually tracking the storms themselves rather than looking at some broader proxy of the storm track. Their results may have implications the frequency of storm events hitting northeastern coastal boundaries, such as those in northeast US and eastern Canada, since storms tend to move poleward more quickly in a warmer climate.”

Tamarin-Brodsky, T. and Kaspi, Y. (2017) Enhanced poleward propagation of storms under climate change, Nature Geosciences, (paywall)

This article was originally posted on Carbon Brief and is shared under a Creative Commons license.

Cover photo by Pete Linforth (public domain).
Past climate lessons prompt present rethink

Past climate lessons prompt present rethink

By Alex Kirby

Climate scientists have been looking again deep into the Earth’s history. Those past climate lessons are not reassuring.

European scientists have just reached two chilling conclusions about today’s Earth by studying past climate lessons. One is that, just as the combustion of fossil fuels is dangerously warming the planet, so too the formation of those fuels turned down the planetary thermostat to deadly levels 300 million years ago.

The second is even more ominous. Swiss scientists say evidence that the world’s oceans were once much warmer may be a misreading. If so, then the current period of climate change has no parallel within the last 100 million years.

The present, said Charles Lyell, the giant of geology, and Charles Darwin’s mentor, is the key to the past. Equally, the past can tell those of us in the present what to expect in the future.

So climate scientists have been probing fossil evidence to read a record of temperature shifts over a 500 million year span – and identify potential explanations of those shifts.

Coal is composed of buried, preserved and altered vegetation from long ago: it is in effect ancient sunshine and carbon from the atmosphere preserved as combustible rock. Georg Feulner of the Potsdam Institute for Climate Impact Research reports in the Proceedings of the National Academy of Sciences that the formation of fossil fuels during the Permian and the Carboniferous was so energetic that carbon dioxide levels in the atmosphere fell steadily, to the point almost of global glaciation.

Earth narrowly escaped a “snowball state.” And the study illuminates the present cycle of climate change. Carbon dioxide levels in the atmosphere fluctuated over time, falling from 700 parts per million to a low of 100 ppm around 300 million years ago by the end of the Carboniferous.

“It is quite an irony that forming the coal that today is a major factor for dangerous global warming once almost led to global glaciation,” Dr Feulner said.

“However, this illustrates the enormous dimension of the coal issue. The amount of CO2 stored in Earth’s coal reserves was once big enough to push our climate out of balance. When released by burning the coal, the CO2 is again destabilising the Earth system.”

And the Earth’s system might in any case have been a little more stable than researchers thought. Around 100 million years ago, deep in the age of the last dinosaurs, the high latitudes were warm and the polar ocean surfaces would have been 15°C warmer than they are now, according to fossil evidence.

Possible over-estimate

But, Swiss and French researchers warn in the journal Nature Communications, this may not be the case. They report that they looked again at the evidence from tiny marine organisms buried long ago, to find what they think could be flaws in the methodology.

If they are right, ocean temperatures in the Cretaceous may have been over-estimated: if so, then the current levels of climate change are even more alarming.

“If we are right, our study challenges decades of paleoclimate research,” said Anders Meibom, head of the laboratory for biological geochemistry at the Ecole Polytechnique Federal de Lausanne, and a professor at the University of Lausanne.

“Oceans cover 70% of our planet. They play a key role in the Earth’s climate. Knowing the extent to which their temperatures have varied over geological time is crucial if we are to gain a fuller understanding of how they behave and to predict the consequences of current climate change more accurately.”

This article was originally published on Climate News Network and is shared under a Creative Commons license (BY-ND 4.0).

Cover photo:
COP23: Fiji’s presidency puts spotlight on climate challenges faced by island nations

COP23: Fiji’s presidency puts spotlight on climate challenges faced by island nations

By Georgina Wade

Fiji’s presidency over COP23 has given Small Island Developing States (SIDS) an invaluable platform to draw attention to the challenges they are facing due to climate change. SIDS are among the most vulnerable to climate change impacts. Their small geographical area, isolation and exposure leaves them particularly susceptible to climate change risks including sea-level rise, cyclones, increasing air and sea surface temperature, and changing rainfall patterns. And although these countries are among the least responsible for climate change, they are likely to suffer the most from its adverse effects and could, in some cases, become completely uninhabitable.

The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) finds that the impacts of climate change will affect the livelihoods, coastal settlements, infrastructure, ecosystems and economic stability in SIDS with sea level rise posing an increasing threats to low-lying islands and coastal areas. Additionally, higher water temperatures will increase the rate of coral bleaching causing a significant rise in coral mortality. For many SIDS, coral reefs are integral to daily life through their contribution to the economy via the tourism and fishing industries and their role as a vital protein source.

A 2005 United Nations Framework Convention on Climate Change (UNFCCC) report warned that SIDS are reaching their tolerance limits with their vulnerability to climate change expected to worsen with each passing year. The sheer magnitude of climate risks to SIDS was evident throughout the 2017 hurricane season which brought an unprecedented series of catastrophically strong storm systems resulting in an estimated $385 billion in economic loss. Labelled as the most powerful Atlantic storm in recorded history, Hurricane Irma brought about the forced abandonment of Barbuda while Hurricane Maria shut down Puerto Rico’s entire electricity service. To further underline the severity of the situation for SIDS, earlier this month a report was released stating that Fiji alone would have to spend about $4.5 billion over the next decade to reach its development objectives while facing climate change impacts.

Despite their small contribution to global emissions, SIDS have worked to remain at the forefront of global climate resilience efforts. Republic of Fiji’s Prime Minister, Frank Bainimarama, made history with Fiji’s presidency over the 23rd United Nations Climate Change Conference (COP23) by becoming the first SIDS to preside over the conference of the parties. This prominent role put a strong emphasis on SIDS, as Bainimarama said, “I bring a particular perspective to these negotiations on behalf of some of those who are most vulnerable to the effects of climate change […] We owe it not to ourselves but to future generations to tackle this issue head on before it is too late.” The Fijian presidency allowed for the prioritisation of topics that are usually not as prominent during the UN climate talks, highlighting not only the challenges faced by SIDS but the importance of cooperation between all parties in facing climate threats.

Cover photo by UNFCCC/Flickr (CC BY-NC-SA 2.0): Timoci Naulusala tells COP23 High-level segment how his home is experiencing the impact of climate change. Watch his speech by clicking here.
2017 is set to be among the three hottest years on record

2017 is set to be among the three hottest years on record

Andrew King, University of Melbourne and David Karoly, University of Melbourne

The year isn’t over yet, but we can already be sure that 2017 will be among the hottest years on record for the globe. While the global average surface temperature won’t match what we saw in 2016, it is now very likely that it will be one of the three warmest years on record, according to a statement issued by the World Meteorological Organization.

What is more remarkable is that this year’s warmth comes without a boost from El Niño. When an El Niño brings warm waters to the tropical east Pacific, we see a transfer of heat from the ocean to the lower atmosphere, which can raise the global average temperatures recorded at the surface by an extra 0.1-0.2℃. But this year’s temperatures have been high even in the absence of this phenomenon.

We can already say with confidence that 2017 will end up being the warmest non-El Niño year on record, and that it will be warmer than any year before 2015. The average global temperature between January to September this year was roughly 1.1℃ warmer than the pre-industrial average.

This trend is associated with increased greenhouse gas concentrations, and this year we have seen record high global atmospheric carbon dioxide concentrations and the biggest recorded surge in CO₂ levels.

A year of extremes

Of course, none of us experiences the global average temperature, so we also care about local extreme weather. This year has already seen plenty of extremes.

Global sea ice extent continues to decline.
NASA Earth Observatory

At the poles we’ve seen a continuation of the global trend towards reduced sea ice extent. On February 13, global sea ice extent reached its lowest point on record, amid a record low winter for Arctic ice. Since then the Arctic sea ice extent has become less unusual but it still remains well below the satellite-era average. Antarctic sea ice extent also remains low but is no longer at record low levels as it was in February and March of this year.

East Africa saw continued drought with failure of the long rains, coupled with political instability, leading to food insecurity and population displacement, particularly in Somalia.

Storms and fires

This year also saw a very active North Atlantic hurricane season. Parts of the southern United States and the Caribbean were struck by major hurricanes such as Harvey, Irma, and Maria, and are still recovering from the effects.

Other parts of the globe have seen a quieter year for tropical cyclones.

There have also been several notable wildfire outbreaks around the world this year. In Western Europe, record June heat and very dry conditions gave rise to severe fires in Portugal. This was followed by more severe fires across Spain and Portugal in October.

Parts of California also experienced severe fires following a wet winter, which promoted plant growth, and then a hot dry summer.

Australia is now gearing up for what is forecast to be a worse-than-average fire season after record winter daytime temperatures. A potential La Niña forming in the Pacific and recent rains in eastern Australia may reduce some of the bushfire risk.

The overall message

So what conclusions can we draw from this year’s extreme weather? It’s certainly clear that humans are warming the climate and increasing the chances of some of the extreme weather we’ve seem in 2017. In particular, many of this year’s heatwaves and hot spells have already been linked to human-caused climate change.

For other events the human influence is harder to determine. For example, the human fingerprint on East Africa’s drought is uncertain. It is also hard to say exactly how climate change is influencing tropical cyclones, beyond the fact that their impact is likely to be made worse by rising sea levels.

The ConversationFor much of 2017’s extreme weather, however, we can say that it is an indicator of what’s to come.

Andrew King, Climate Extremes Research Fellow, University of Melbourne and David Karoly, Professor of Atmospheric Science, University of Melbourne
This article was originally published on The Conversation. Read the original article.
Cover photo by Raimund Bertrams (public domain).