That extra half a degree makes a huge difference. At a maximum global average warming of 2°C above the norm for most of human history, the Arctic could become technically ice-free once every three to five years.
Reduce carbon dioxide emissions even further, take greater steps to conserve forests and keep the global temperature at the 1.5° C maximum rise, and the chances are that the Arctic seaways will open only about one summer in 40 years.
Glaciologists consider the Arctic “ice-free” when there are only a million square kilometres of floe left. It has yet to happen. But the sea ice has become noticeably thinner, and smaller in surface area, over the last 40 years.
“The good news is that the sea has a quick response time and could theoretically recover if we brought down global temperatures . . . though other ecosystems could see permanent negative impacts from ice loss”
For more than two decades, meteorologists and oceanographers have repeatedly warned that runaway global warming, as a consequence of ever-greater combustion of fossil fuels, could bring about an ice-free polar ocean by about 2050.
Sea ice is part of the climate machine. It reflects solar radiation and keeps the ocean cool. It provides a surface on which Arctic seals can haul out, and on which polar bears can feed.
But the catch is that, although the world’s nations almost unanimously voted in Paris to contain global warming, the pledges made at the time were nowhere near ambitious enough.
US and Canadian climate scientists set out to see what difference half a degree would make to the Arctic. They worked with different climate simulations to reach roughly the same conclusion, in two papers in the journal Nature Climate Change.
The Canadian team calculated that at 2°C, ice-free conditions would happen every five years; at 1.5°C, the hazard would drop to one in 40 years; at 3°C, permanent ice-free summers would be likely. A second study from the US backed up the premise.
“I didn’t expect to find that half a degree Celsius would make a big difference, but it really does,” said Alexandra Jahn, of the University of Colorado at Boulder.
“At 1.5°C half the time we stay within our current summer sea ice regime, whereas if we reach two degrees of warming, the summer sea ice will always be below what we have experienced in recent decades.”
Higher levels of warming would impose higher costs: 4°C of warming would deliver a high probability of an ocean free of ice for three months every summer by 2050, and five months a year by 2100.
“The good news is that the sea has a quick response time and could theoretically recover if we brought down global temperatures at any point in the future,” Dr Jahn said.
“In the meantime, though, other ecosystems could see permanent negative impacts from ice loss, and those can’t necessarily bounce back.”
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.
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.
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 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.
Scientists 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.
While Houston is still reeling from the impacts of Hurricane Harvey, it appears that one of the city’s main vulnerabilities were its vast impervious surfaces. Concrete, asphalt and various types of surface materials prevent the absorption of water into the soil, and when gallons of rain pour down on urban areas, drainage systems get saturated. Ecosystems could make a substantial contribution to flood risk reduction and enhance urban resilience.
In the case of Hurricane Sandy, a study demonstrated that the presence of marsh wetlands avoided $625 million in direct flood damages across 12 states, as coastal wetlands reduced flood heights. This illustrates that ecosystems can greatly contribute to flood prevention, in particular for low-lying cities. There are different types of ecosystems that can increase cities’ resilience to flooding. However, many of these ecosystems are threatened by human activity, and initiatives are currently being implemented to mainstream their use and strengthen the resilience of low-lying and coastal cities.
Wetlands are diverse and can be found at different locations. For instance, marshes, areas of grassy vegetation and peaty soil, are common in floodplains while tidal wetlands, characterised by reeds, mangroves and mudflats, are located at river mouths. Forested wetlands and ponds are additional wetland types that can absorb large amounts of water runoff and help regulate overland floods. Besides, other forms of ecosystems, such as coral reefs, play an important role in protecting low-lying urban areas. They provide natural barriers against wave energy, an essential aspect to consider when it comes to storm surges and rising sea levels, and act against coastal erosion. Consequently, protecting those ecosystems is essential to leverage the potential flood protection they provide. Wetlands are currently threatened by manmade activities such as new build-up or pasture areas that convert them into non-wetland zones, pollution emanating from untreated wastewater and vegetation clearing. These decrease the wetlands’ capacity to hold back and absorb water.
There currently exist several initiatives that focus on protecting and using those ecosystems against floods. In Bangladesh for example, an initiative funded by the Least Developed Country Fund, focuses on coastal afforestation as a way to increase community resilience. Part of the project is dedicated to planting protective and productive vegetation, including mangroves, to protect communities’ livelihoods from extreme weather events and sea level rise.
Cover photo: U.S. Marine Corps photo by Lance Cpl. Niles Lee/Released (public domain). Marines unload supplies to assist families in Orange, Texas, Sept. 3, 2017. The Marines assisted the Red Cross by transporting supplies from the Red Cross warehouse to families in Orange, Texas, affected by Hurricane Harvey.
To remedy the situation, would putting an economic value on these natural marvels succeed in drawing global attention to the issue? That’s the purpose of a recent Deloitte study that estimated the GBR to be worth $56 billion. This indicative figure captures the GBR’s economic and social value in order to elevate its significance in decision and policy-making. Concrete insights show that the reef contributed 64,000 jobs to the Australian economy in 2015-2016 and that tourism alone derived $29 billion in value.
Although it is hard to assess whether monetising coral reefs has a direct impact on their conservation, tangible figures highlight how environmental preservation is beneficial to human activities and development. So, if we are to price coral reefs, why not also bring in the insurance industry to cover them, as we do for other economic assets? This idea is actually currently being implemented in Mexico, where an insurance scheme has been set up to protect the reef off the Cancún coast. Local tourism-dependent organisations contribute between $1 million to $7.5 million to a collective pot, which will be used to cover storm-induced damages to the reef system.
This scheme, run by Swiss Re and the Nature Conservancy with backing from the Mexican government, illustrates how a public-private partnership can achieve complementary economic and environmental benefits. Trying to understand the economic value of natural resources can help decision makers from the public and business sectors better manage them and improve their resilience to climate change.
However, these approaches are new and the world has already lost half of its coral reefs over the past 30 years. As scientists expect 90% of global corals to be lost by 2050 if no drastic actions are taken, all issues that affect corals in addition to climate change impacts, such as overfishing and run-off from coastal areas, should be seen as priorities now.
Cover photo by Acropora/Wikimedia (CC BY 3.0): Bleached branching coral (foreground) and normal branching coral (background). Keppel Islands, Great Barrier Reef.
Channel 4 News Science Editor Tom Clarke travelled to Norway’s Svalbard Islands at the end of last year’s Arctic summer to see the profound effect climate change is having on the (not so) icy North.
The Arctic is warming at a much higher rate than the rest of the Earth putting a fragile ecosystem at risk. Additionally, Arctic ice melt has the potential to have devastating effects around the globe triggering tipping points and intensifying feedback loops that will affect global climate.
Throughout the video a deep rumble can be heard in the background, it is the sound of a crumbling glacier. Tom Clarke’s guide explains, “every year the snowmelt is earlier… wherever I look there is obvious change.” They stand on muddy ground which was once buried underneath a glacier, but that ice has retreaded over a 1km in less than a decade.
Watch the full video to see how disproportionate warming is affecting the Arctic:
Cover photo by NASA/GISS (Public Domain). This image shows trends in mean surface air temperature over the period 1960 to 2011. Notice that the Arctic is red, indicating that the trend over this 50 year period is for an increase in air temperature of more that 2° C (3.6° F) across much of the Arctic, which is larger than for other parts of the globe. The inset shows linear trends over the period by latitude.
In an age of rapid global population growth, demand for safe, clean water is constantly increasing. In 2010 the United States alone used 355 billion gallons of water per day. Most of the available fresh water on Earth’s surface is found in lakes, streams and reservoirs, so these water bodies are critical resources.
As a limnologist, I study lakes and other inland waters. This work is challenging and interesting because every lake is an ecosystem that is biologically, chemically and physically unique. They also are extremely sensitive to changes in regional and global weather and long-term climate patterns.
For these reasons, lakes are often called “sentinels of change.” Like the figurative canary in the coal mine, lakes may experience change to their ecosystem dynamics before we start to see shifts in the greater watersheds around them.
While many groups have studied the long-term impact of climate change on lakes, this process can now be added to the growing list of drivers of eutrophication. This is a potentially damaging phenomenon that could affect a number of vital deep-water lakes around the world, degrading water quality and harming fish populations.
The impact of too many nutrients
Eutrophication is a condition that occurs when lakes and reservoirs become overfertilized. Cultural eutrophication is a well-understood process in which lake and reservoir ecosystems become overloaded with chemical nutrients, mainly nitrogen and phosphorus. These nutrients come from human activities, including fertilizer runoff from farms and releases from sewage systems and water treatment plants. Natural weathering processes, atmospheric deposition of air pollutants, and erosion also transport nutrients that are already present in the watershed into the water supply.
In water bodies, these heavy nutrient loads fertilize algae, causing surface algal blooms. When the algae die, they sink and are broken down as they decompose. This decomposition process consumes dissolved oxygen in the water. As oxygen levels become depleted, hypoxic (dead) zones develop in the bottom waters where oxygen levels are too low to support life. Dead zones harm fisheries and tourism, and algal blooms can contaminate drinking water.
Over the past several decades, state and federal regulators have developed many initiativesto eliminate or reduce nutrient sources. In some cases, such as Seattle’s Lake Washington, water quality has improved through management. In other, larger watersheds – notably, the Great Lakes – nutrient pollution is still a major problem.
Climate change and mixing in lakes
As anyone who has swum in a lake knows, the water is typically warmest on the surface where the sun shines on it. Cold water is denser than warmer water, so it sinks. For much of the year, deep lakes will remain stratified (separated into layers).
In fall and late winter, large storms disrupt natural stratification and cause lake waters to overturn. This mixes surface waters down into the lake’s depths and brings deep water up to the surface, where it can absorb oxygen from the atmosphere. This process, which transfers dissolved oxygen from the surface to the lake bottom, is critical for an ecosystem’s health.
But our study showed that surface warming in Lake Tahoe could cause climatic eutrophication by reducing or even ending mixing, thus interrupting the vertical movement of dissolved oxygen from the lake’s surface to the lake bed.
Scientists, spearheaded by the University of California – Davis, have been monitoring conditions at Lake Tahoe for nearly 50 years, so we have good records of short- and long-term changes in water temperatures and quality. Since 1968, the average temperatures of the lake’s surface waters (down to a depth of 80-120 feet) have increased by nearly 0.5 degrees Celsius. That change has increased the lake’s stability – a measurement of how resistant it is to overturning – enough to reduce the probability that surface waters will mix all the way to the lake bottom.
To model possible future conditions, we estimated Lake Tahoe’s annual stability by combining a lake hydrodynamic model – representing how water is moved around the lake – with two different greenhouse gas emission scenarios published by the Intergovernmental Panel on Climate Change. In one scenario, emissions increased rapidly throughout this century; in the other, emissions leveled off by the year 2100.
As the lake remains stratified for longer periods each year and less overturning occurs, dissolved oxygen levels at the bottom will decline. Under these conditions, nutrients stored in the lake bed will be released to the water through chemical reactions that occur in low-oxygen environments. This new source of nutrients, known as internal loading, will further contribute to the process of climatic eutrophication.
Although all lakes are unique ecosystems, this process could also occur in other deep-lake settings around the world, such as Japan’s Lake Biwa or Lake Baikal in southeastern Siberia. Climate change is already shortening the periods each year when many temperate and polar lakes are covered with ice. As water temperatures rise in the upper layers of deep lakes, they will remain stratified for more of the year and will be less subject to mixing. Less dissolved oxygen will be returned to deep waters, which will stress fish populations.
And unlike cultural eutrophication, climatic eutrophication could affect entire watersheds or regions, since it is driven by climatic influences rather than by discharges of nutrients into a lake from farms or cities.
Climatic eutrophication has serious implications for long-term water supplies and aquatic ecosystem health around the world. To recognize and track it, we need to identify lakes in North America and around the world that could be at high risk.
In areas where scientists and regulators are working to reduce conventional eutrophication, these experts will also need to factor the possibility of climate-forced eutrophication into their strategies. The first step is to support more monitoring of lakes’ physics and chemistry so that we can recognize, track and predict climatic eutrophication of our lakes and reservoirs.
At the same time, coffee-growing regions are shrinking and shifting. Farmers are being forced to move to higher altitudes, as the band in which to grow tasty coffee moves up the mountain.
The evidence that climate change is affecting some of our most prized beverages is simply too great to be ignored. So while British sparkling wine and the beginning of the “coffeepocalypse” were inconceivable just a few decades ago, they are now a reality. It’s unlikely that you’ll find many climate deniers among winemakers and coffee connoisseurs. But there are far greater impacts in store for human society than disruptions to our favourite drinks.
Dramatic examples of climate-mediated change to species distributions are not exceptions; they are fast becoming the rule. As our study published recently in the journal Scienceshows, climate change is driving a universal major redistribution of life on Earth.
These changes are already having serious consequences for economic development, livelihoods, food security, human health, and culture. They are even influencing the pace of climate change itself, producing feedbacks to the climate system.
Species on the move
Species have, of course, been on the move since the dawn of life on Earth. The geographical ranges of species are naturally dynamic and fluctuate over time. But the critical issue here is the magnitude and rate of climatic changes for the 21st century, which are comparable to the largest global changes in the past 65 million years. Species have often adapted to changes in their physical environment, but never before have they been expected to do it so fast, and to accommodate so many human needs along the way.
Different species respond at different rates and to different degrees, with the result that new ecological communities are starting to emerge. Species that had never before interacted are now intermingled, and species that previously depended on one another for food or shelter are forced apart.
This global reshuffling of species can lead to pervasive and often unexpected consequences for both biological and human communities. For example, the range expansion of plant-eating tropical fish can have catastrophic impacts by overgrazing kelp forests, affecting biodiversity and important fisheries.
In wealthier countries these changes will create substantial challenges. For developing countries, the impacts may be devastating.
Many changes in species distribution have implications that are immediately obvious, like the spread of disease vectors such as mosquitoes or agricultural pests. However, other changes that may initially appear more subtle can also have great effects via impacting global climate feedbacks.
Mangroves, which store more carbon per unit area than most tropical forests, are moving towards the poles. Spring blooms of microscopic sea algae are projected to weaken and shift into the Arctic Ocean, as the global temperature rises and the seasonal Arctic sea ice retreats. This will change the patterns of “biological carbon sequestration” over Earth’s surface, and may lead to less carbon dioxide being removed from the atmosphere.
Redistribution of the vegetation on land is also expected to influence climate change. With more vegetation, less solar radiation is reflected back into the atmosphere, resulting in further warming. “Greening of the Arctic”, where larger shrubs are taking over from mosses and lichens, is expected to substantially change the reflectivity of the surface.
These changes in the distribution of vegetation are also affecting the culture of Indigenous Arctic communities. The northward growth of shrubs is leading to declines in the low-lying mosses and lichens eaten by caribou and reindeer. The opportunities for Indigenous reindeer herding and hunting are greatly reduced, with economic and cultural implications.
Winners and losers
Not all changes in distribution will be harmful. There will be winners and losers for species, and for the human communities and economic activities that rely on them. For example, coastal fishing communities in northern India are benefiting from the northward shift in the oil sardine’s range. In contrast, skipjack tuna is projected to become less abundant in western areas of the Pacific, where many countries depend on this fishery for economic development and food security.
Even with improved monitoring and communication, we face an enormous challenge in addressing these changes in species distribution, to reduce their adverse impacts and maximise any opportunities. Responses will be needed at all levels of governance.
Internationally, the impacts of species on the move will affect our capacity to achieve virtually all of the United Nations Sustainable Development Goals, including good health, poverty reduction, economic growth, and gender equity.
Currently, these goals do not yet adequately consider effects of climate-driven changes in species distributions. This needs to change if we are to have any chance of achieving them in the future.
National development plans, economic strategies, conservation priorities, and supporting policies and governance arrangements will all need to be recalibrated to reflect the realities of climate change impacts on our natural systems. At the regional and local levels, a range of responses may be needed to enable affected places and communities to survive or thrive under new conditions.
For communities, this might include changed farming, forestry or fishing practices, new health interventions, and, in some cases, alternative livelihoods. Management responses such as relocating coffee production will itself have spillover effects on other communities or natural areas, so adaptation responses may need to anticipate indirect effects and negotiate these trade-offs.
To promote global biodiversity, protected areas will need to be managed to explicitly recognise novel ecological communities, and to promote connectivity across the landscape. For some species, managed relocations or direct interventions may be needed. Our commitment to conservation will need to be reflected in funding levels and priorities.
The success of human societies has always depended on the living components of natural and managed systems. For all our development and modernisation, this hasn’t changed. But human society has yet to appreciate the full implications for life on Earth, including human lives, of our current unprecedented climate-driven species redistribution. Enhanced awareness, supported by appropriate governance, will provide the best chance of minimising negative consequences while maximising opportunities arising from species movements.
Melting in the Arctic region is uncovering unwelcome waste, pollutants and diseases that were once thought to be ‘preserved for eternity’. Melting of glaciers, tundra and sea ice is taking place at a rate that is uncovering radiological waste, sewage and even Anthrax.
A military camp built beneath the surface of Greenland ice sheet during the Cold War was left abandoned in 1967, leaving behind a heap of waste which included 200,000 litres of diesel fuel, 24 million litres of biological waste in the form of sewage, and radiological waste. The waste was left in the belief the snowfall would continue falling and the waste would be “preserved for eternity”.
However, due to climate change, Greenland has lost 1 trillion tons of ice over the period of four years between 2011 and 2014. There is worry that the melting and the unearthing of this waste has potential to expose great amounts of hazardous materials. Arctic regions experience warming from climate change at almost twice the global average.
In the northern arctic region of Russia in 2016 there was an outbreak of Anthrax, it caused the death of a 12-year-old boy and hospitalised 90 people. This episode is reported to be a result of climate change as the 10°C warmer than average temperature melted the permafrost of a previous burial site for animals that died of anthrax 70 years ago.
If climate change predictions are correct and the melting of permafrost continues, we could see more cases of disease outbreaks. Infections from the 18th and 19th century could re-emerge, especially near the unknown cemeteries and burial sites where victims were buried.
In Russia, the thawing of permafrost and flooding has led to greater erosion of river banks where the dead were once buried. Researchers are worried that the thawing human and animal remains may lead to the re-emergence of diseases such as Spanish flu virus, which have been found in bodies buried in mass graves in Alaska’s tundra, as well as the smallpox virus and bubonic plague buried in Siberia.
Though some researchers argue that the prospect of a killer infection to appear from melting permafrost is unlikely, it does raise troubling questions about what is locked in the vast frozen landscapes of the north.
Cover photo by NASA Earth Observatory (Public Domain)
The influential British sociologist Anthony Giddens has argued that we live in a “high-risk, high-opportunity society.” While innovation is opening up astounding new possibilities, globalized societies also face immense and complex risks, not least of which is climate change.
Today, over half of the world’s population live in cities. The United Nations estimates that by 2050, this number will be well over 60 per cent. We know that cities will face climate change impacts such as more frequent and intense extreme weather events, and thus need policies that will protect people and their livelihoods, as well as reducing the costs associated with these impacts.
Despite the severity of the challenge, there also an opportunity for cities to develop innovative policies to build resilience to such risks in ways that will make our cities healthier, more vibrant and more economically prosperous. As much as cultivating craft breweries and high-tech start-ups, resilience is going to be a key factor in making our cities attractive places to live and do business.
The Canadian province of Alberta is no stranger to managing climate risks. One report by a federal working group notes that the province has been “hit by 7 of the 10 most expensive disasters in Canadian history.”
The initiative I co-lead, the Prairie Climate Centre (PCC), has created an interactive Prairie Climate Atlas that visualizes climate change impacts anticipated in the province. These include less predictable weather and greater risk of extreme weather such as flash floods, severe rainstorms, heat waves and droughts, among others.
Albertans have demonstrated impressive resilience strategies to withstand disasters in the past. However, climate change will bring new threats and costs, which will require redoubling efforts to on-going efforts to manage climate risks. In a series of new reports prepared for Alberta’s two largest cities—Calgary and Edmonton—my colleagues and I have painted the broad strokes of the types of policies they can adopt to build their climate resilience. The three principles that underlie these policies are: robustness, redundancy and resourcefulness.
First, we need to enhance our cities’ robustness, designing physical features in the urban landscape that will help cities cope with high-impact climate events. Biodiversity is crucial, as features like trees on streets and significant ecological sites like mature forests and wetlands are valuable assets in cities facing climate change impacts like more frequent floods and droughts.
Second, cities need redundancy, which is to design systems that have the capacity to function despite disruptions and surges in demand. This could mean more reliance on heavily decentralized energy generation coupled to modular storage technologies, using smart irrigation technologies to reduce wastewater and increase potable water sources, and promoting green roofs to absorb stormwater runoff to rainwater to reduce flooding.
Third, cities need to adopt policies that encourage resourcefulness. Citizens and institutions need to be aware of climate risks, able to adapt to shocks and stresses and able to quickly respond to a changing environment. This could include, for example, designing transportation systems that encourage public and active transportation, and using technology that allows citizens feedback into the system (apps that allow users to identify hazards like potholes or flooding, or highlight areas that could be improved to accommodate active transport users like cyclists).
Each city is unique and will need to chart its own course to resilience building. Our new reports highlight a suite of potential options. For cities, building resilience is a ‘win-win’ — managing climate risks is the driving force behind adopting such policies, but they also make cities better places to live and do business.
An active commitment to building resilience through investing in innovative infrastructure is essential urban policy and smart investment. Edmonton and Calgary are demonstrating this type of commitment, and we can hope the strategies they develop can help lead other cities across Canada and around the world to make a similar shift from risk to resilience.
Dr. Hank Venema is director of planning for the Prairie Climate Centre, a joint initiative of the University of Winnipeg and the International Institute for Sustainable Development (IISD).
Australia’s Great Barrier Reef and reefs in the Maldives have been dangerously weakened by coral bleaching caused by global warming and El Niño events.
The Great Barrier Reef, one of the wonders of the Pacific Ocean, may never fully recoverfrom the combined effects of global warming and an El Niño year, according to a new study in one of the world’s leading science journals.
But the world’s oceans are becoming hotter anyway, because of global warming driven by greenhouse gas concentrations in the atmosphere. The seas are becoming ever more acidic as atmospheric carbon dioxide reacts with the water.
And the periodic return of a blister of oceanic heat in the eastern Pacific called El Niño – Spanish for “The Child”, because it becomes most visible around Christmastime – has begun to put the world’s reefs at risk. The El Niño of 2015-16 triggered a massive episode of bleaching throughout the tropics. And, Australian researchers say in Nature, the bleaching continues.
“We’re hoping that the next two to three weeks will cool off quickly, and this year’s bleaching won’t be anything like last year. The severity of the 2016 bleaching was off the chart,” says Terry Hughes, of Australia’s Centre of Excellence for Coral Reef Studies, at James Cook University in Queensland.
“It was the third major bleaching to affect the Great Barrier Reef, following earlier heatwaves in 1998 and 2002. Now we’re gearing up to study a potential number four.
“We have now assessed whether past exposure to bleaching in 1998 and 2002 made reefs any more tolerant in 2016. Sadly, we found no evidence that past bleaching makes the corals any tougher.”
The reefs are among the richest ecosystems on the planet, and they provide vital coastal protection for human settlements as well as a source of sustainable protein for human economies.
“It broke my heart to see so many corals dying on northern reefs on the Great Barrier Reef in 2016,” says Professor Hughes. “With rising temperatures due to global warming, it’s only a matter of time before we see more of these events. A fourth event after only one year is a major blow to the Reef.”
British scientists saw much the same devastation from the same El Niño bleaching around the Maldives in the Indian Ocean, they write in Scientific Reports journal. And the big question now is: how quickly can the Indian Ocean reefs recover?
Growth rate of reefs
“Recovery from similar past disturbances in the Maldives has taken 10-15 years, but major bleaching events are predicted to become far more frequent than this. If this is the case it could lead to long-term loss of reef growth and so limit the coastal protection and habitat services these reefs presently provide,” says Chris Perry, professor of physical geography at the University of Exeter, UK.
“The most alarming aspect of this coral die-off event is that it has led to a rapid and very large decline in the growth rate of the reefs.
“This in turn has major implications not only for the capacity of these reefs to match any increases in sea-level, but because it is also likely to lead to a loss of the surface structure of the reefs that is so critical for supporting fish species diversity and abundance.”
This article was originally published on Climate News Network and is shared under a Creative Commons license.
Read more about the current coral bleaching event in the Great Barrier reef: