A fungal disease that attacks banana crops is on the rise
thanks to climate change, suggests new research. Black Sigatoka, also known as
“black leaf streak,” has been on the move since the 1960s from Asia
to areas now including the Caribbean, Latin America and most recently to parts
The research found that changes to moisture and temperature
conditions as a result of climate change have increased the risk of Black
Sigatoka by more than 44 percent in affected areas during the past six decades.
“This research shows that climate change has made
temperatures better for spore germination and growth, and made crop canopies
wetter, raising the risk of Black Sigatoka infection in many banana-growing
areas of Latin America,” said the study’s lead author Daniel Bebber of the
University of Exeter.
The study makes no predictions about what future climate
change might mean for the spread of the fungus or the risk to future banana
crops throughout the world. However, it is indicative of the increased risk of
pests and diseases that many crops face as global temperatures rise.
Ecologists have long conceived of the earth as a living organism where every plant, animal, river and cloud are interconnected.
In the political sphere, however, the climate and biodiversity crises have more often than not remained solidly bunkered away from each other. That could be changing.
A series of major meetings are pushing the governments of the world to address both crises as one. Experts hope they could lead to a major shift in the way we think about tackling climate change.
On Monday, a new blockbuster report revealed that up to one out of eight million known plant and animal species could be at risk of extinction.
Global warming is the third biggest factor driving species extinction after changes in land and sea use and the direct exploitation of organisms, according to the report by the UN’s biodiversity science body IPBES. A hike in temperature of just 1C has impacted life from the level of ecosystems to that of genetics. At 1.5C to 2C of warming – the goals of the Paris climate agreement – the report warns the ranges of most of the world’s species on land will shrink significantly.
But this relationship, as scientists and politicians increasingly note, isn’t only negative: often – though not always – conservation efforts bolster the climate too. Healthy ecosystems are imperative for the earth’s capacity to mop up C02.
“We know that ecosystems are currently absorbing 25% of emissions. Another 25% of our emissions are going into the oceans, which is causing ocean acidification,” Guy Midgley, a coordinating lead author of the report, said on Monday. “Together, that’s half of our emissions not ending in the atmosphere because of the health of our ecosystems.”
Meanwhile, evidence of the critical role of certain animals in the maintenance of these ecosystems continues to stack up. Known in zoology as cornerstone species, the beaver is vital to wetlands through dam construction, the scaly pangolin protects forests from termite ravages, while by stomping vegetation, African forest elephants encourage the growth of larger trees capable of absorbing more carbon.
It is estimated that so-called ‘nature-based solutions’, which benefit climate and biodiversity, could provide 40% of the carbon emissions cuts needed by 2030 to give a decent chance of limiting warming below 2C. Yet they receive less than 3% of climate funding.
Conservationists familiar with diplomatic negotiations on biodiversity and climate change complain of bureaucratic ghettos. The two UN programmes, the Convention on Biodiversity (CBD) and UN Framework Convention on Climate Change (UNFCCC), don’t really talk to each other, Beatriz Luraschi, a researcher on climate change and biodiversity at the UK nature charity RSPB, told Climate Home News.
While “the CBD has always been more inclusive of other issues, including climate change,” Luraschi said, citing a decision passed at the CBD in 2018 in Egypt calling on states to slash emissions through ecosystems, “the same level of interest in biodiversity has never been reflected in the same formal setting in the UNFCCC. Even though there is some language in the Paris Agreement on maintaining environmental integrity, it just isn’t as explicit.”
This is changing. Frances Seymour, a senior fellow at the World Resources Institute (WRI), notes that there is growing appetite within the UN for literature on the crossovers, with a major report by the think tank due to be released in September.C
“It’s great that people are connecting the dots,” Seymour told CHN. Forest and land emissions have long been a “stepchild in the broader climate world”, she said, which has focused on energy and other fossil fuel sources. The proximity of the IPBS report to a recent major release from the UN’s climate science panel has helped focus attention on the crossover.
The momentum to bring the two issues together is set to pick up at a flurry of critical gatherings in the next 18 months. UN chief Antonio Guterres will be calling on governments to present plans to slash emissions at a climate action summit in September. In December, climate talks in Chile are expected to focus on the importance of ocean health.
In autumn 2020, China will host a landmark summit on biodiversity in Kunming. The meeting is set to define new biodiversity targets, with expectations running high after governments failed to meet goals (2011-2020) formulated during the CBD in Aichi, Japan in 2010. Many hope this to be biodiversity’s Paris moment.
“People can’t help but see them as milestones in one roadmap towards either disaster or redemption,” Seymour said.
Overall, diplomatic initiatives aimed at tackling both crises are on the rise. With the meeting of G7 environment ministers coinciding with the publication of the IPBS report, heads of state issued the Metz Charter on Biodiversity. The non-binding document called on the group to recognise the vital role of biodiversity in contributing to climate regulation and helping communities combat natural disasters. The group also committed to deploy “nature-based solutions… which can also enhance climate change mitigation and ecosystem restoration.”
Meanwhile, China (alongside New Zealand) is heading a UN working group on nature-based solutions, in the run-up to September’s climate action summit in New York. The aim is to encourage states to incorporate nature-based solutions in their climate pledges to the Paris Agreement.
Seymour hopes governments will put their money where their mouths are. “We haven’t seen a shift yet in financial resources… We’re off by an order of magnitude,” Seymour said. If countries update their climate commitments to include serious efforts on nature it “will really embody whether we’re serious about this or not”.
But this effort is not without obstacles, Li Shuo at Greenpeace China told CHN. “I think one challenge that this track faces is that the topic of nature-based solutions was sort of overlooked by the climate community. There wasn’t much diplomatic groundwork done on this issue.”
With land-use, agriculture and nature-related sectors contributing less than 10% of Chinese emissions, “energy and transportation-related issues are traditionally perceived as our climate issue”, Li said. “It’s a new learning process for government officials who are chairing this track.”
“The challenge for China is twofold: it has to start the action domestically. In the context of the the UN Climate Action Summit, China’s job is about inspiring the entire membership of the UN on this particular topic,” Li said.
When it comes to biodiversity, China and France are developing their own visions of leadership. The Chinese government is “now paying very close attention to the negotiations” leading to next year’s CBD meeting, with “the entire bureaucracy mobilised to deliver a good outcome”, Li told CHN.
But France, the host of the Paris Agreement, is pursuing a grander vision – a new overarching global treaty for nature. Back in 2017, Emmanuel Macron floated the idea of a treaty that would aid cooperation on environmental blights, such as plastics, but also the biodiversity and climate crises.
Next year, the port city of Marseille is set to host the World Conservation Congress. President of International Union for Conservation of Nature Zhang Xinsheng described the event as “central in mobilising the international community ahead of critical decisions to be taken later that year regarding global efforts to tackle biodiversity loss and climate change”.
Be ready for climate hazard in a new form – the compound heat waves that hit you, leave you, and come back again.
As the world warms, say US scientists, the risk of economically devastating, physically debilitating and potentially lethal extremes of heat will multiply, and in unexpected ways.
Researchers picture a world in which the most vulnerable – those already ill or elderly, housed in substandard buildings in crowded cities – are laid low and gasping by several days of extreme heat. Even if the temperatures drop a little, the buildings in which they live will still “store” heat to intolerable levels.
And then, unexpectedly, the extremes of heat return. Hospitals could be overwhelmed. Electric grids might experience overload. Harvests could wither. And the weakest could dehydrate and die.
“Averaged over time, heat waves are the most deadly type of disaster in the United States, in addition to causing many emergency room visits, lost working hours and lower agricultural yields,” said Jane Baldwin of Princeton University in the US.
“Surveys of low income housing in places such as Harlem have found that after a heat wave has ended, temperatures indoors can remain elevated”
“However, if you look at the deadliest heat waves in Europe and the United States, many have more unusual temporal structures with temperature jumping above and below extremely hot levels multiple times.”
Climate scientists have repeatedly warned that as the planet warms overall, the number of places where potentially deadly heat waves will hit will inevitably rise.
If humans go on burning fossil fuels at ever-increasing levels, then heat waves usually experienced once a century could return every few years, to become the “new normal.”
The Princeton study, in the journal Earth’s Future, is a preliminary look simply at the probabilities of back-to-back heatwaves. Policymakers, city authorities and medical chiefs need to know what new hazards global heating can bring, and the study is, the scientists say, just a first step.
But it identifies the precise problems that come with severe temperatures, especially for the already vulnerable, even in the world’s richest cities, such as New York.
“Surveys of low income housing in places such as Harlem have found that after a heat wave has ended, temperatures indoors can remain elevated for a number of days,” Dr Baldwin said. A swift return of the big heat could multiply the stresses.
And her co-author Michael Oppenheimer said: “We want to know how the effects of compound heat waves will differ from – and amplify – the already severe consequences for human health, infrastructure stability and crop yield that we see from single event heat waves.”
The people who are responsible for calculating insurance
risks and premiums have ranked climate change as the top risk for 2019.
Actuaries rated climate risk as a bigger threat to insurers than cyber-crime,
financial instability, and terrorism.
The survey, published by the Joint Risk Management Section, found that over a fifth of the 267 actuaries surveyed, identified climate change as their number one emerging risk. Climate change was also the most significant combination risk, and importantly, was also tied first (with cyber/infrastructure) for the top current risk, putting paid to the idea that climate change is an issue for the future.
As one might expect, the insurance industry is ahead of the
curve in terms of assessing climate risk exposure. However, because it is able
to adjust its premiums regularly – typically on an annual basis – it is able to
account for climate risk. Policy holders on the other hand, will see their
premiums rise inexorably, until there is an unaffordability crisis.
Actuaries that are able to correctly account for climate risks are able to include price signals in premiums ahead of time, helping to encourage investment away from areas of high climate exposure. This would include, for instance, reckless lending on coastal real-estate in areas vulnerable to sea level rise.
The survey is a good indication that concern about climate
risk is growing in the industry. Last year, fewer than one in ten respondents
rated climate change as the top emerging risk.
Institutional Investors Group on Climate Change (IIGCC) has launched a new
project to develop guidance for investors on how they integrate the risks and
opportunities presented by the physical risks of climate change in their
investment research and decision-making processes.
The project will develop an IIGCC
investor guide focusing on physical climate risk analysis with technical input
from the specialist advisory firms Acclimatise and Chronos Sustainability, in
collaboration with IIGCC members.
leading the initiative with the support of the Universities Superannuation
Scheme (USS), one of the UK’s largest pension funds. Stephanie Pfeifer, CEO,
Institutional Investors Group on Climate Change, explains: “In many ways, adaptation is the missing issue in the
climate change debate. IIGCC’s new initiative will help investors to understand
its importance and act on adaptation to climate change as an investment issue.
This includes ensuring investors have the practical tools to account for the
physical risks of climate change and are able to act on the opportunities found
in addressing the issue, across both investment decisions and company
Russell, Head of Responsible Investment at USS, adds: “One of the key contributions of this project
will be to focus on the risk posed by climate change across a range of
asset classes. This will include sectors that are both dependent on access to
water and other environmental resources, and those potentially impacted by a
The new guidance will include an introduction to the investment implications of physical climate hazards, and will collate information on tools and data sources needed to manage physical climate risks. Available later this summer, the guidance also aims to propose a process that investors can go through to identify, assess, manage and disclose climate-related physical risks and opportunities across their portfolios.
The United Nations Environment Programme has shown that the cost of necessary adaptation to climate change is between $140 to $300 billion per year across the global economy by 2030 alone, and point to a major gap in adaptation finance[. This offers potential new investment opportunities, in which investors can help build broader climate resilience, while also mitigating future losses otherwise incurred. This initiative will help investors better understand the nature of this opportunity.
The initiative is delivered as part of IIGCC’s ‘Investor Practices’ programme, which helps asset owners and managers better assess and manage both climate risk and opportunity, and to report on their actions more effectively.
The Global Report on Internal Displacement reveals that 9.6 million new displacements were recorded in East Asia and the Pacific, and 3.8 million in South Asia in 2018. The drivers of internal displacement are complex including conflict, geophysical events such as earthquakes, and increasingly, extreme weather events.
The report finds that East Asia and the Pacific remains a
disaster hotspot, with the Philippines and China accounting for 7.6 million new
displacements last year. Most of these were pre-emptive evacuations as typhoons
“It is the same countries affected year after year and,
while the relative impacts and resilience to respond varies hugely across the
region, over time resources and coping mechanisms are being eroded.” said
Alexandra Bilak, IDMC’s director. “We must invest more heavily in strategies
that reduce people’s exposure and vulnerability to the risks that cause
Climate-related extreme weather events dominated
displacement in many countries. For example, monsoon rains and flooding
displaced hundreds of thousands in Myanmar, while Japan was struck by an
unusually high number of disasters from storms to landslides. Flooding also affected
many small island states in the Pacific.
Such events dwarfed displacement by conflict and violence in
the region, most of which occurred in the Philippine region of Mindanao and
Myanmar’s Kachin and northern Shan states.
In South Asia, India recorded around 2.8 million new
displacements, among the highest figures in the world. Monsoon floods,
particularly in the south-western state of Kerala, and cyclones were
responsible for the majority. The monsoon season also brought significant
flooding to both Sri Lanka and Bangladesh. Drought triggered 371,000 new
displacements in Afghanistan, a similar number to those associated with the
country’s ongoing conflict.
The report also highlighted that internal displacement is
increasingly becoming an “urban phenomenon”, with people moving from their
rural homes to find safety in cities. Dhaka, for example, is the preferred
destination for many internally displaced people fleeing climate change impacts
in coastal regions of Bangladesh. However, rapid urbanisation is also increased
displacement risk. Cities in East Asia, for example, are expanding in areas
highly exposed to hazards, such as the tropical cyclone belt and the Pacific
Ring of Fire.
“The fact that cities have become sanctuary to more and more
internally displaced people represents a challenge for municipal authorities,
but also an opportunity.” Said Bilak. “Leveraging the positive role that local
government can play in finding solutions to displacement will be key to
addressing this challenge in the future.”
Nature based solutions, including coral reef restoration and artificial coral reefs, protect one of tourism’s primary draws – the beach.
White sandy beaches and year-round summer temperatures attract tens of millions of tourists each year to destinations like the Caribbean. Tourism remains a vital source of economic development for tourist hotspots. Even in countries with a colder climate, where beaches don’t attract international acclaim, they are often places of community gathering and recreation.
beach is an attraction in and of itself and, at the same time, provides coastal
protection for communities and infrastructure from erosion and in-land flood
risk. However, beaches themselves are prone to degradation by extreme weather
events (such as hurricanes) and daily tidal activity, thereby reducing the
beaches aesthetic appeal and capacity for coastal protection. Maintaining beach
resilience should, therefore, be an important priority for coastal and
Various technologies have been deployed world-wide for beach protection, with the ‘quick and dirty’ solution being sand re-nourishment projects. In the U.S. the government has funded to the order of US$ 9 billion for such projects, which entail the dumping sand in regions where beaches have eroded. This option is costly and temporary and to a long-term problem that is likely to worsen with climate change. Construction of hard and semi-hard infrastructure (such as sea-walls, groynes and breakwaters) have also been deployed globally and in certain instances have provided important coastal protection services. However, they carry the possibility of to adjacent non-protected areas and are considered an eye-sore in scenic and tourist areas.
In recent years, natural and hybrid approaches to beach erosion and sand loss have been piloted. These Nature-based Solution (NbS) include coral reef restoration, artificial coral reef construction, natural engineering projects, and sand and dune restoration. NbS can protect against beach erosion, while delivering a series of co-benefits, some of which may generate income streams. For example, coral reefs can dissipate up to 97% of incident wave energy and provide revenue generating opportunities associated with snorkeling, diving, fishing, aquarium trade and more. There is no one-size-fits all solution to the site-specific complexity of beach erosion, however several innovative examples illustrate how NbS can be leveraged to offer coastal protection services.
What are Nature Based
There are an abundance of NbS
definitions, and no universally accepted one. In short, NBS are those that that
are designed, inspired or supported by nature. Here’s one definition from the
European Commission’s Directorate General for Research and Innovation: NbS are solutions
“which aim to help societies address
a variety of environmental, social and economic challenges in sustainable ways,
including actions which are inspired by, supported by or copied from nature. NbS
use the features and complex system processes of nature, such as its ability to
store carbon and regulate water flow, in order to achieve desired outcomes,
such as reduced disaster risk, improved human well-being and socially inclusive
get a better understanding of what this entails, it is helpful to look at
examples from practice around the world.
Now Jade Hotel, Mayan Riviera Mexico, Artificial Coral Reef
The Now Jade Riviera
Cancún Resort and Spa (“Now Jade”) is located in the popular tourist
destination of Puerto Morelos, Mexico on the Mayan Riviera, in close proximity
to the Mesoamerican reef. In 2008, Now Jade embarked on a long-term beach
restoration program focused on the construction of two modular artificial reefs
and future restoration of the sand-dune ecosystem.
Prior to 2007, the
Puerto Morels beach experienced a pattern of sand accretion in summer months
and retreat during winter months, with sufficient year-round sand for tourist
activities. In 2007, the coast was hit by hurricane-induced waves which caused
high volumes of sand to travel from north to south. An adjacent breakwater
stopped the longitudinal currents and induced chronic erosion of the beach. In
2010, with the beach narrowing with on-going erosion, it was decided that beach
resilience efforts were necessary to regenerate the sand.
Several options for
coastal protection were considered including hard structures. However, tourist-specific
considerations required that the structure be not only aesthetic, but also
ecologically friendly. An artificial coral reef was selected for the following
reasons; reefs are effective at wave energy dissipation, the proximity of the
Mesoamerican Reef would facilitate species colonization, the dynamics of sand
transport had already been negatively affected by the existing breakwater and
the artificial reef would bolster the conservation and tourist appeal of the
Following a series of site-specific assessments and laboratory tests, the reefs, made out of pre-fabricated concrete elements, were constructed 120 meters offshore. Five years after construction, an assessment showed that the reefs have contributed to beach recovery, with a natural growth and retreat cycle, and attracted fish and coral colonies from the nearby Mesoamerican Reef. An influx of Sargassum seaweed in 2015 created a temporary decline in reef colonization, however since then the reef has been recovering biological richness in the absence of human intervention.
Mayacoba Resorts: Coastal restoration project
is home to four luxury resorts located on the Mayan Riviera; Andaz Mayakoba, RoseWood
Mayakoba, Fairmont Mayakoba and Banyan Tree Mayakoba. As with other beaches in
the region, Mayakoba has experienced significant sand loss to the order of 15
feet per year since 2005, spurred by two hurricane events. This presents
significant challenges for resorts, which off the primary attraction of long,
white sandy beaches for guest enjoyment. Furthermore, beach erosion could negatively
impact 150 acres of protected mangroves surrounding the resorts, which are home
to alligators, turtles, and various bird species, and even further undermine
the resorts coastal resiliency.
in consortium with local organizations, embarked on reef restoration efforts to
enhance coastal protection services and biodiversity. Scientists transplanted
fragments from a coral nursey onto a concrete grid on the ocean floor on the
Mayakoba coast. The artificial reef is expected to connect with the nearby
existing natural reef to form a self-sustaining colony, capable of providing
coastal protection services.
of spring 2018, initial trials were performing well with the Elkhorn coral
thriving in the concrete barriers. It is expected to take two years for the
coral to mature into a strong colony and four years for the coral to start
reproducing. Once mature, the reef is expected to help protect Mayakoba beaches
from erosion, and attract fish and marine life to create a more desirable
attraction for snorkelers and divers.
Fairmont even offers a ‘Coral Reef Restoration Package’ where guests can
participate in restoration efforts as a part of their stay. Twenty Five percent
of revenues from this package are redirected to fund reef restoration efforts. The
resort is able to capture an additional revenue stream through this package,
offering an additional economic incentive for investment in coastal
are a series of challenges that could compromise the corals restoration
efforts, and the services they provide. This includes coral bleaching driven by
increased sea surface temperatures and sunlight exposure, sargassum influx,
extreme events (i.e. hurricanes that cause structural damage to the reef, and
industrial run-off. The inability to effectively regulate the anthropogenic activities
(i.e. greenhouse gas emissions, and agricultural runoff) creates a challenge
for the successful revival of coral reefs.
Netherland’s Sand Motor
The Dutch have long been striving to protect their low-lying country from sea level rise and coastal erosion. In the past, the sand dunes on the Dutch peninsula were replenished every 5-year, via sand shipment from the North Sea. However, the Dutch wanted to pilot a lasting solution that would allow the country’s southwest beaches to regenerate on their own, a popular kite-surfing destination and recreational area for the urban population.
creation of the Sand Motor, a large artificial hook shaped peninsula, changed
the dynamics of the winds, waves and currents to gradually spread sand along
the coast and form a new dune landscape and wider beach. The sand motor was
initially constructed with 21.5 million cubic meters spread across an area of
128 hectares, and natural processes are expected to add an additional 35
hectares to the coast over a 10 km stretch in the next 20 years. By depositing
a large volume of sand at once, the sand motor avoids repeated disruption to
Preliminary 5-year results of the Sand Motor show that it is acting mostly as expected, supplying sand to a five kilometer stretch of beach, with 1.5 million cubic meters of sand moved to the north, and nearly 1 million cubic meters moved to the south. Only dune growth in the coastal area near the Sand Motor is progressing slower than expected. The expansion of the beach has provided a greater area for community recreation and outdoor activities, and has become somewhat of a tourist attraction in itself. Long-term analysis of the Sand Motor (20 years) will ultimately show whether it is a viable solution, and can be reproduced as a coastal management strategy in other countries.
Please see this publication for further information on the Sand Motor.
Challenges of these projects and steps forward
These case studies provide insight into a variety of NbS that can be deployed for coastal protection. The solutions are not driven by an ecological imperative, but rather a coastal protection one that delivers ecological co-benefits. This distinction is important as it puts NbS on the same playing field as engineered solutions. A solution that effectively fulfills the coastal protection imperative in a cost-effective way, while delivering a series of co-benefits (that traditional infrastructure does not) will generate win-win results for businesses, communities and tourists.
Despite the dramatic news coverage of oil spills and other big pollution disasters in our seas and oceans, most environmental pollution is caused by much smaller incidents that are often invisible, persistent, and far more difficult to track.
While animals and plants caught up in these disasters are easily identified as stressed or physically affected by the pollution, with smaller incidents, organisms might look and behave perfectly normal. Only over time does the chronic exposure to low-level pollution take its toll.
By the time this becomes obvious, often it is too late to do anything to save a particular population, whose decline might have knock-on effects on the surrounding environment, often with socio-economic consequences. So there is not only a moral responsibility to look after the environment, but also a strong financial incentive, because many jobs and livelihoods depend on a healthy environment and its ecosystems.
Biomarkers of exposure provide a tool to identify pollution events early on, often at levels that are not detectable by conventional methods. Loosely defined as measurable effects (endpoints) in organisms, providing evidence of exposure to pollutants, biomarkers lead to establishing the cause and giving the necessary data to inform any policy decisions that need to be taken.
Such biomarkers exist in a number of biological areas. They can be purely biochemical, manifesting themselves as damages to DNA, alterations to the activity of enzymes involved in metabolism, structural damage to cells and their subsequent ability to perform properly, as well as more obvious pathological, reproductive or behavioural disorders. However, this requires intimate knowledge of the species and the relevant environmental variables, including how these may influence the respective biomarkers.
The latest Intergovernmental Panel on Climate Change (IPCC) reports on climate change show that the upper 75 metres of the world’s oceans have been warming at a rate of 0.11°C per decade since at least 1971 and the uptake of CO2 caused by human pollution has depressed pH (acidity level) by -0.0014 to -0.0024 per year, and is predicted to continue.
Effects of climate change
These changes are likely to affect biomarkers on three levels. First of all, commonly used organisms may no longer be available, as they migrate further north in search of cooler water. And they may then be replaced by invasive species from warmer waters that are not be as sensitive to pollution and therefore not as useful as biomarker organisms. Changing migratory patterns may increase the transport of contaminants in the bodies of organisms in significant quantities to other, previously clean locations, in some cases even becoming more important than wind or water-driven methods.
Second, the fate and behaviour of contaminants in the environment, particularly their persistence, their ability to be taken up by organisms and how they behave once absorbed, is strongly driven by environmental factors such as salinity, pH and temperature – and these are all subject to change under climate change scenarios. This means, organisms may be more or less susceptible to pollutants; the degree of change will depend on the specific pollutants and the organism species involved.
Last of all, organisms unable to migrate will experience increased stress owing to changes in temperature, salinity and pH which may mean they may no longer be sensitive enough for the biomarker task.
A major focus of research in my lab is working towards re-evaluating these biomarkers in several mainstream organisms and assessing the potential of new, better-adapted organisms. The main aim of this work is to future proof our tools for detecting pollution in the marine environment in order to maintain the ecosystem we all depend on.
The evidence for climate change driven by pollution caused by humans is overwhelming and it is clear it is affecting the marine environment. As a result, some commonly used biomarker species and endpoints may need to be re-evaluated and adapted for this changing environment if they are to be used in future as early warning systems for pollution.
As cities across the global South grapple with climate change, many are designing plans to deal with escalating climate impacts including erratic precipitation and unpredictable shifts in temperature. And in response to global agendas such as the Sustainable Development Goals and the Paris Agreement, these plans seek to integrate basic development priorities while improving access to basic services including water, sanitation and health.
Many approaches encourage decision-makers, scientists, and NGOs to participate in the planning process. However, ‘participatory’ processes often leave marginalised groups out of the picture.
This is particularly true in the global South where high levels of economic inequality, absence of effective leadership, and prevalent political corruption hinders socially accountable and sustainable processes to manage the impacts of climate change.
Both cities have progressive plans for adapting to climate change and managing growing climate risk. Still, previous research notes that these cities’ plans tend to favour certain politically important groups, and economically important assets such as buildings located in central business districts.
Why are supposedly participatory adaptation plans exclusionary or inequitable? How do we make sense of this contradiction?
Case study: Bengaluru
In the southern city of Bengaluru, studied under the Adaptation at Scale in Semi-Arid Regions (ASSAR) project, we explored how migrants living in flood- and diseases prone informal settlements are coping with exposure to climate change. Precarious living circumstances are compounded by exposure to heat stress often experienced during manual labour such as waste-picking.
Added to these climate vulnerabilities, long standing social constructs deepen migrants’ challenges. Given their status as unskilled, landless labourers, migrants are regarded as ‘out-of-state’ citizens. This includes members of the Other Backward Classes (OBC) – a term used by the Indian government that encompasses educationally, economically and socially disadvantaged groups.
These groups do not have access to formal public services such as state-based health schemes and subsidised rations of water, foodstuffs and basic supplies. In the event of a disaster, migrants are the most prone to illness and death.
However, subsequent plans to implement adaptation programmes focused on the needs of local business, leaving out the city’s migrant population.
Eventually, plans began to target flood protection for businesses and insulation for formal housing. In the name of ‘urban development’ or ‘climate resilience’, many informal settlements were razed to make way for building flood protection measures and to reinforce embankments.
Having been left out of the plans, migrant communities were forced to relocate. Their increasing exposure to climate risks and lack of political representation led to their displacement, breaking the valuable social and economic networks they need to survive.
Our study shows that city planners persistently fail to recognise migrants in urban adaptation plans and policies. In Bengaluru and Surat, political ideologies, social values, and access to economic opportunities combined work against marginalised groups, excluding them from these plans and processes.
We need a new vocabulary around social justice that recognises the interests, needs and voices of historically marginalised groups.
Adaptation plans must intentionally allow spaces for recognising class, caste, gender and age-related implications of proposed actions. Planning processes must take the inclusion of all urban residents seriously – not only those who are privileged, knowledgeable or powerful. This will help to promote plans that bridge the vast inequalities in economic and political power across the global South.
Our influence on the Earth’s environment has lasted for a century: the human impact on droughts and moisture patterns began at least 100 years ago, researchers now say.
US scientists used new analytic techniques and almost a thousand years of tree-ring data to build up a picture of drought and rainfall worldwide for the last century. And they report in the journal Nature that they have identified the human fingerprint upon climate variation as far back as the first days of the motor car and the infant aircraft industry.
The pattern of change, in which regions prone to drought such as the western US became more arid, grew visible between 1900 and 1949. The researchers saw the same pattern of drying in those decades in Australia, Europe, the Mediterranean, western Russia and southeast Asia.
At the same time more rain and snow fell in western China, much of central Asia, the Indian subcontinent, Indonesia and central Canada.
“The big thing we learned is that climate change started affecting global patterns of drought in the early 20th century. We expect this pattern to keep emerging as climate change continues.”
For four decades it has been a given of climate change research that average planetary warming will intensify all the extremes of weather: in particular, drought and flood.
“All the models are projecting that you should see unprecedented drying soon, in a lot of places”
The problem has been that droughts and floods have always happened. But could scientists identify the signature of human change – the clearing of the forests, the intensification of agriculture, the growth of the cities and the ever-increasing use of fossil fuels to dump ever more carbon dioxide in the atmosphere – in any one flood or drought? Until this century, researchers were unwilling to name the guilty party.
The Nasa-led research is not quite the first to claim to have detected very early evidence of climate change. A team led by Chinese scientists reported in April in the journal Nature Sustainability that tree ring evidence from the Tibetan plateau suggested that humans may have begun altering the pattern of seasonal temperatures – that is, the differences between winter and summer – as early as the 1870s, at least in the northern hemisphere.
But the latest study from Dr Marvel and colleagues identifies such evidence on a wider scale, and may even have resolved the puzzle of the extremes that did not happen.
The research found three distinct periods of change. The first was marked by more drought in some places, more precipitation in others in the first half of the 20th century. But by the height of the Cold War, and the space race mid-century, it became harder to see a pattern, and climate events seemed more random, and climates cooler.
The researchers now think the huge volumes of aerosols from power stations, factory chimneys and vehicle exhausts between 1950 and 1975 altered weather patterns in different ways, affecting cloud formation, rainfall and temperature, to mask the effect of greenhouse gas increases.
These were the years of choking smog, grime and soot, sulphurous droplets, acid rain, corroding historic buildings and urban respiratory disease on an epidemic scale.
Stronger pattern expected
And then developed nations started introducing clean air legislation and other pollution controls. Round about 1981, tentative evidence of the impact of human-driven greenhouse gas emissions began to show again in the climate record, although not as boldly as in the first half of the century.
If the researchers have got it right, the pattern of increasing drought, matched elsewhere by increasing precipitation, will continue to become stronger.
“If we don’t see it coming in stronger in, say, the next 10 years, we might have to wonder whether we are right,” Dr Marvel said. “But all the models are projecting that you should see unprecedented drying soon, in a lot of places.”
And the researchers warn that the consequences for humankind, especially in North America and Eurasia, could be severe.