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A new study has found that marine heatwaves have become more than 20 times more frequent over the past four decades due to the burning of greenhouse gases. 

A marine heatwave is an extended period of time in which the water temperature in a particular ocean region is abnormally high. The study, published in the journal Science, is the first to look at the anthropogenic impacts on marine heatwaves and was conducted by a team of marine scientists at the University of Bern in Switzerland. By examining satellite measurements of sea surface temperatures from 1981 to 2017, the team found that these heatwaves have become longer, hotter and more frequent. 

In the 1980s, satellites recorded 27 major marine heatwaves, which each lasted about a month with water temperatures reaching a maximum of 4.8 degrees Celsius above average. In the last 10 years, there were 172 major heatwaves across the globe, lasting 48 days on average with temperatures reaching a maximum of 5.5 degrees above average.

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Heatwaves can have lasting, detrimental effects on marine ecosystems. Warmer temperatures can trigger algal blooms, impact on nutrient availability, cause coral bleaching and change fish migration patterns. 

In pre-industrial times, extreme marine heatwaves similar to those seen in the past decade would have occurred once every few hundred to thousands of years. However, the team found that if global temperatures rise 1.5 degrees Celsius- the goal of the Paris Agreement- these heatwaves could happen once a decade or century. If temperatures increase by 3 degrees Celsius, these heatwaves could become as frequent as once a year of decade. 

Charlotte Laufkӧtter, one of the authors of the study, says, “Ambitious climate goals are an absolute necessity for reducing the risk of unprecedented marine heatwaves. They are the only way to prevent the irreversible loss of some of the most valuable marine ecosystems.”

Antarctica experienced unprecedented heat this summer, with a heatwave that began in late spring in the Antarctic Peninsula and circumnavigated the continent over the next four months. Since the late 19th century, the planet has warmed by roughly 0.8°C. Scientists predict that the Earth’s temperature may increase by 3-5°C by the end of the century. This poses a massive problem for the fastest-warming regions on Earth, one of which is the Antarctic Peninsula. What does it mean when the coldest place on Earth heats up?

While isolated from the rest of the world, Antarctica drives the global ocean conveyor belt, a constantly moving system of deep-ocean circulation which transfers oceanic heat around the planet; Antarctica demonstrates the patterns of change that we can expect to see in other parts of the world.

According to the World Meteorological Organization (WMO), the Esperanza research base on the Antarctic Peninsula reported a temperature of 18.4°C on February 6, the hottest on record for the continent, which was eclipsed three days later, when a nearby research station recorded a temperature of 20.75°C, the continent’s first time to exceed 20°C in recorded history. 

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What Caused the Heatwave in Antarctica?

The Casey Station recorded a heatwave from January 23 to 26; on January 24, the maximum temperature was 9.3°C, almost 7°C above the Station’s 30-year mean for the month.

The arrival of warm, moist air amid this weather brought rain to the Davis Research Station in the normally cold desert of the Vestfold Hill. These conditions spurred meltwater pools and surface streams on local glaciers. These, along with melting snowbanks, contributed to high-flowing rivers and flooding lakes.

Antarctica Melting Rate

Further, the amount of ice flowing from the Thwaites Glacier, one of the biggest culprits in rising sea levels, has nearly doubled over the last three decades. A 2018 study reveals that ice shelf collapse from 1992 to 2017 increased the Antarctic Peninsula ice loss rate from 7 to 33 billion tons a year. 

In January, researchers recorded what they consider to be the biggest widespread melting of the George VI ice shelf, which is right beside the Antarctic Peninsula. The exact reason for this is unknown, but scientists surmise that the warm temperature likely affects other Antarctic regions as well.

Satellite images from February 2019 to February 2020 revealed that a huge iceberg from the Pine Island Glacier broke off into smaller pieces. This unprecedented heatwave in Antarctica and the sea level rise driven by the melting of the glaciers will lead to disastrous consequences. 

NASA’s Earth Observatory also reports that Antarctica’s warm temperatures began on February 5 and lasted until February 13, the period when the hottest temperature was recorded on the Esperanza base.

The weakened state of the Southern Hemisphere westerlies due to Antarctic Oscillation is a big factor as it normally shields warm weather from being transported from Earth’s temperate regions to the Antarctic Peninsula. The polar cyclone is at its maximum intensity during the winter and it reaches its weakest during the summer, weakening the westerlies. Dry and warm foehn winds may have also contributed as they release heat into the air. 

The late Indian monsoon retreat, the most delayed it has been in 60 years, caused the water in the Indian Ocean to be warmer than usual as an effect of the ‘positive’ state of the Indian Ocean Dipole (IOD). This positive IOD may have lasted until January, also contributing to the warmer temperature in the Antarctic regions. 

High-temperature trends in the Antarctic Peninsula give a clearer depiction of the continent’s climate, which is essential in observing rising sea levels and global warming conditions. An increase in these trends will cause further melting of the glaciers which intensifies extreme events brought about by the climate crisis.

According to WMO Deputy Secretary-General Elena Manaenkova, every seemingly insignificant degree of global warming will affect food security, access to clean water, species extinction and economic productivity. In addition to this, Pacific Island nations, such as Kiribati and Samoa, and coastal communities will most likely be displaced.

A paper by the WWF says that a 4°C increase in global temperature would melt nearly all the glaciers on Earth. Ocean warming may have caused more than half of Antarctica’s total ice loss during the last few years, especially in the eastern Antarctic Peninsula.

“It is worth repeating once again that we are the first generation to fully understand climate change and the last generation to be able to do something about it,” said WMO Secretary-General Petteri Taalas.

Since the 19th century, the global average sea level has increased by over 15cm. Concrete and realistic plans by global leaders paired with transformative climate action would address the current climate crisis. These events highlight how interconnected our climate systems are, from the surface to the stratosphere and from the monsoon tropics to the southernmost continent. An unprecedented heatwave in Antarctica is a sign of things to come for the rest of the planet and to avoid irreversible and devastating impacts, there is no better time to act than the present.

Featured image by: Daniel Enchev

A new study in Science Advances has found that intolerable bouts of potentially fatal humidity and heat are on the rise around the world, suggesting that worst-case scenario warnings about the impacts of the climate crisis are already happening. 

Humans’ ability to efficiently shed heat has enabled us to survive on every continent, but a wet-bulb temperature (TW) of 35°C marks our upper physiological limit. Previous climate models projected the first 35°C TW incidents by mid-century, and mostly in parts of the tropics and subtropics where humidity is already a problem. However, the study found that some coastal subtropical locations have already reported a TW of 35°C and that extreme humid-heat weather has more than doubled in frequency since 1979. Researchers identified thousands of previously undetected outbreaks of the weather combination in parts of Africa, Asia, Australia and South and North America, including several spots along the US Gulf coast. 

In the US, regions that experienced such extreme conditions dozens of times include eastern Texas, New Orleans and Biloxi, Mississippi. The most extreme incidents occurred along the Persian Gulf, where the heat-humidity combination surpassed the theoretical human survivability threshold on 14 occasions. 

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Slightly less extreme but more frequent outbreaks were detected across India, Bangladesh and Pakistan, north-western Australia and coastal regions along the Red Sea and Mexico’s Gulf of California.

Colin Raymond, lead author of the study, says, “Previous studies projected that this would happen several decades from now, but this shows it’s happening right now. The times these events will last will increase, and the areas they affect will grow in direct correlation with global warming.”

The team of researchers analysed hourly data from 7 877 individual weather stations, allowing them to pinpoint localised incidents.

In dry conditions, the body sweats out excess heat and evaporates it away, however humidity affects this evaporation and can even halt it in extreme conditions. If the body exceeds the threshold of survivability, organs will fail and lead to death within hours. 

Meteorologists measure the heat/ humidity effect on the ‘wet bulb’ scale. A normal internal human body temperature of 36.8° ± 0.5°C requires skin temperatures of around 35°C to remain comfortable. In theory, once the air temperature exceeds 35°C, humans will not be able to survive; this was the peak suffered in small areas of Saudi Arabia, Qatar and the UAE.

While some heat-humidity impacts can be avoided through acclimation and behavioural adaptation, humans can only withstand so much before survivability is impaired, even with perfect health, total inactivity, full shade, no clothing and unlimited drinking water.

Results suggest that under business-as-usual scenarios, wet bulb temperatures could regularly exceed 35°C in parts of South Asia and the Middle East by the third quarter of this century.

While air conditioning can mitigate the impact of heat-humidity, they are harmful to the environment and are not an option for most people in poor high-risk countries where subsistence farming is common. 

Featured image by: BrunoAmaru

A new UN report has warned that climate change could trigger a global food crisis. The report outlines possible solutions including sustainable land management and increasing food productivity.

How will climate change affect food production?

The United Nations climate report warns that the world might face a food crisis due to climate change and overexploitation of land and water resources. A steady increase in global temperatures will make things worse, as floods, drought, storms, and other types of extreme weather threaten to disrupt the global food supply. 

The Intergovernmental Panel on Climate Change (IPCC) report, prepared by more than 100 experts from 52 countries and released in Geneva last week, reveals that humans affect more than 70% of ice-free land and a quarter is already degraded. Rapid agricultural expansion has led to destruction of forests, wetlands, grasslands, and other ecosystems. Soil erosion from agricultural fields is 10 to 100 times higher than the soil formation rate. Such rapid land degradation has created spinoff effects.

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“When land is degraded, it becomes less productive, restricting what can be grown and reducing the soil’s ability to absorb carbon,” says the report. “This exacerbates climate change, while climate change in turn exacerbates land degradation.”

The report also reveals that an estimated 23% of all greenhouse gas emissions that significantly warm the planet are caused by agriculture, cattle rearing, and deforestation. 

A warming atmosphere intensifies the world’s droughts, heat waves, wildfires, and other weather patterns, and it is further speeding up the rate of soil loss, land degradation, and desertification. “Since the pre-industrial period, the land surface air temperature has risen nearly twice as much as the global average temperature,” the report says “climate change, including increases in frequency and intensity of extremes, has adversely impacted food security and terrestrial ecosystems as well as contributed to desertification and land degradation in many regions.”

Possible solutions 

Warning that the window to address threats of climate change, food security, and land degradation is closing rapidly, the report offers a variety of solutions to address the challenges. 

Tactics like improving food productivity and increasing the carbon content of soil can simultaneously mitigate climate change, help regions adapt to warming, stop desertification, reverse land degradation, and enhance food security.

“The options with medium to large benefits for all challenges are increased food productivity, improved cropland management, improved grazing land management, improved livestock management, agroforestry, improved forest management, increased soil organic carbon content, fire management, and reduced post-harvest losses,” the report says.

Enhancing food productivity means using less land for agriculture, which could help preserve forest land retaining a natural carbon intake system. Those forests move moisture through the biome and help regulate temperature, reducing the impacts of warming. Trees in the preserved forest anchor the soil, slowing erosion and preventing desertification. That stabilising effect in turn helps reduce volatility in crop yields, enhancing food security.

Sustainable land management is an effective solution. “Land management can prevent and reduce land degradation, maintain land productivity, and sometimes reverse the adverse impacts of climate change on land degradation. It can also contribute to mitigation and adaptation,” says the report. “Reducing and reversing land degradation, at scales from individual farms to entire watersheds, can provide cost-effective, immediate, and long-term benefits to communities and support several Sustainable Development Goals (SDGs) with co-benefits for adaptation and mitigation.” 

Reducing food waste is another important solution. The report estimates that over 30% of food is lost or wasted, which has environmental costs as food waste accounts for upward of 10% of global greenhouse gas emissions. If the world were to drastically limit food waste, farmers would need less land, less fuel, less water, and less fertiliser, all of which would translate to a smaller environmental footprint. “Technical options such as improved harvesting techniques, on-farm storage, infrastructure, transport, packaging, retail, and education can reduce food loss and waste across the supply chain,” the report states. “By 2050, reduced food loss and waste can free millions of square kilometers of land.”

A new study predicts that three quarters of the world’s major cities will experience dramatic climate shifts in their weather by 2050.

 —

Environmental Predictions 2050

New York, San Francisco, and Washington will face unprecedented weather, while London will suffer from extreme drought by 2050, a recent study that analysed the impacts of climate change on the world’s major cities predicts. The effects of global heating will be so severe that the cities in temperate or cold zones in the northern hemisphere will be as hot as cities that are 1 000 km closer to the equator.

The research paper published in the peer-reviewed science journal PLOS ONE states that summers and winters in Europe will get considerably warmer by 2050, with average increases of 3.5C and 4.7C, respectively, compared with 2000. Water shortages will affect scores of cities in Europe as a result of the heating. The climate in London will look more like the climate in Barcelona, which suffered a major drought in 2018 resulting in millions of euros being spent on importing drinking water. Madrid will feel like Moroccan city Marrakech, Stockholm like Budapest, and Moscow like Bulgarian capital city Sofia.

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“New York City winters will be as warm as winters in Virginia Beach and wet Seattle will be as dry as San Francisco,” says the paper. “Washington D.C. will be more like today’s Nashville but with even greater variation in temperatures and precipitation.”

The residents of about a fifth of cities globally–including Jakarta, Singapore, Yangon, and Kuala Lumpur–will experience conditions currently not seen in any major cities in the world.  Rainfall will be a particular problem for such cities, with extreme flooding becoming more common alongside more frequent and severe droughts.

a) Cities in red – predicted to experience novel climate conditions. Cities in green – predicted to experience climate conditions similar to those of another major city. Size of dots represents size of change. b) The proportion of cities shifting away from the covered climate domain. c) and d) Extent of latitudinal shifts in relation to the equatorial line. Cities in blue – shifting towards the equator. Cities in yellow to red – shifting away from the equator. © 2019 Bastin et al./PLOS ONE

The researchers used state-of-the-art climate model projections of existing data. Analysing city pairs for 520 major cities in the world, they produced insights that are more meaningful to the common public. For instance, their interactive map shows different cities and their 2050 counterparts regarding weather patterns.

Cities’ Contribution to Climate Change

Cities are key contributors to climate change with urban activities causing the majority of greenhouse gas emissions. Estimates suggest that cities are responsible for 75% of global CO2 emissions, with transport and buildings being among the largest contributors.

Meanwhile, climate change is already impacting urban life across the world. With exceptional heatwaves striking across Europe last month, new temperature records were set in many cities in Belgium, the Netherlands and Germany as the mercury went above 40C. A new UK heat record was set with 38.7C in Cambridge.

In the US, millions of people were affected as the temperature soared in New York, Boston, Atlanta, and many cities in the Midwest. Millions in India also suffered as heatwaves and water shortages became severe in cities like Mumbai and Chennai. In Japan, more than 5,000 people from various urban centers sought treatment due to a heatwave in July.

Climate change will have costly impacts on cities’ basic services, infrastructure, housing, and health. It is essential, therefore, to make cities an integral part of the solution in fighting climate change by building more renewable energy infrastructures and introducing cleaner production techniques, and regulations or incentives to limit industrial emissions.

 

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