What is already happening to our weather?
More extreme weather
“World leaders should be listening not just to scientists but also to the people who are being affected by extreme weather events right now. They are seeing it with their own eyes and suffering from it. Humanity just won’t be able to cope with the world we are heading for.”Professor Peter Stott, the Met Office
“The analysis clearly shows climate change has already changed our weather patterns and is having adverse effects on people’s lives. It is beholden on all governments to take heed of these warnings and start cutting carbon emissions as quick as possible.”Professor Mark Maslin, University College London
“We are seeing increases in extreme weather events that go well beyond what has been predicted or projected in the past. We’re learning that there are factors we were not previously aware of that may be magnifying the impacts of human-caused climate change… Increasingly, the science suggests that many of the impacts are occurring earlier and with greater amplitude than was predicted”Professor Michael Mann, Director of the Earth System Science Center at Pennsylvania State University
Global heating is having a huge impact on our natural weather systems. This is because the increased amount of heat energy trapped in the Earth’s atmosphere and oceans (as a result of greenhouse gas emissions) increases the total amount of energy in our weather systems. As a result, global heating doesn’t just cause an overall rise in global temperatures, it also leads to more frequent and more extreme heatwaves, heavier rainfall, and more intense tropical storms and hurricanes. Generally, wetter areas are getting wetter, increasing the risk of flooding, and dryer areas are getting drier, increasing the risk of droughts and forest fires.
There also is growing concern that global heating might be causing further disruption to our weather by weakening the jet stream – an air current that carries air around the globe and contributes to worldwide weather patterns. It is thought that a weakening of this current could lead to a “blocking” of our weather systems, increasing the likelihood of extreme weather events such as storms and floods, and making heatwaves and droughts last for longer periods of time. This could also explain why some areas are having more extreme cold periods despite the world getting hotter overall.
The number of extreme climate-related disasters – including extreme heat, droughts, floods and storms – has doubled since the early 1990s and studies have shown that more than two thirds of all extreme weather events investigated were made more likely, or more severe, by human-caused climate change.
Such extreme weather events are having devastating impacts on agriculture, leaving millions of people in need of humanitarian aid and costing taxpayers billions of dollars. In the first six months of 2019, extreme weather events displaced a record seven million people from their homes.
It should be noted that the total number of people killed by such events is actually decreasing – an argument used by climate skeptics to claim that such events are not getting more frequent. On the contrary, this just shows that we are getting better at predicting extreme weather events and getting people out of harm’s way in time. Looking only at death rates massively misrepresents the human, agricultural and financial impacts of the ever-increasing numbers of extreme weather events.
Indeed, the economic costs of damage caused by natural disasters are skyrocketing. Whilst its true to say that ‘natural disasters’ include those not related to climate change, and economic costs can go up simply due to there now being more infrastructure that can be damaged, we know that financial losses due to extreme weather events are rising faster than those due to non-climate related disasters, such as Earthquakes.
Indeed, in 2017 extreme weather disasters caused overall losses of US$340 billion, the second-highest annual loss ever. Less than half of these losses were covered by insurance. According to Morgan Stanley, from 2016-2018 climate-related disasters cost the world $650 billion.
Christiana Figueres, former United Nations’ Climate Chief, warned: “We are moving towards a world that the insurance industry calls systemically uninsurable because the degree of destruction will be such that the insurance companies cannot deal with the level of risk that would be brought upon us. The expense of a constant construct, reconstruct, reconstruct, frankly, no country can afford.”
The McKinsey Global Institute Climate Risk and Response Report 2020 warned: “Greater awareness of climate risk could make long-duration borrowing more expensive or unavailable, impact insurance cost and availability, and reduce terminal values. This could trigger capital reallocation and asset repricing. This recognition could happen quickly, with the possibility of cascading consequences.”
The following sections explain some specific ways in which global warming is already affecting our weather. Follow the links to read about how extreme weather is predicted to be impacting our world by 2050 or by the end of the century.
Longer and more intense heatwaves
“These records will be broken in a few years. What we see with European heatwaves is that all the climate models are underestimating the change that we see.”Friederike Otto, Associate Professor Climate Research Programme, University of Oxford
As global temperatures increase, not only does the average day in many locations become hotter, but the chance of extremely hot days is greater too – increasing the frequency and intensity of heatwaves. Indeed, studies have shown that human-induced warming has made scorching heatwaves significantly more likely and also more intense when they hit. There have now been more than 230 attribution studies around the world and these have found that 95% of heatwaves were made more likely or worse by climate change.
Heatwaves are intensified in areas where the land is already dry, as dry soils can’t absorb as much heat. As a result, more heat is radiated back into the atmosphere, leading to even more sustained heating. This worrying feedback loop can trigger ‘mega-heatwave’ events. See section on drying soils and mega-heatwaves.
The mega-heatwave that struck Europe in 2003 was made at least twice as likely due to climate change and approximately 70,000 more people died than usually die in an average year – the vast majority of these deaths were directly attributable to the extreme temperatures. This record breaking heatwave also had a massive impact on ecosystems across Europe and caused over $15 billion in economic losses. A more recent analysis from 2014 calculated that, due to the warming seen in just the course of a decade, a similarly extreme event is already about ten times more likely than in 2003.
During the Russian mega-heatwave of 2010, made at least three times more likely by man-made climate change, Russia’s wheat harvest declined by 40% – contributing to a global wheat shortage as well as a 90% increase in international grain prices – leading to economic losses of more than $15 billion.
In 2017, 157 million more people worldwide were exposed to heatwaves than in 2000, and hotter weather contributed to the loss of 153 billion hours of labour (a 60% increase from 2000) as workers in construction, farming and other industries had to stop work, often reducing the family income. In India, heat caused the number of hours worked to fall by almost 7%, whilst in England and Wales there were 700 more deaths than normal during a 15-day hot spell in June and July.
In 2018, unprecedented heat and wildfires that “could not have occurred without human-induced climate change” swept across the northern hemisphere with at least 224 locations around the world experiencing all-time record-breaking heat. A record 220 million more over 65s were exposed to heatwaves compared with 2000. The sweltering heat that the UK experienced that summer was made 30 times more likely by climate change. The 2018 heatwave in Japan, which led to over 1,000 deaths, was so severe that researchers said that it “could not have happened without global warming.”
In 2019 nearly 400 temperature records were broken across 29 countries, with July being the hottest month ever recorded. Studies show that the searing mega-heatwaves that summer would have been extremely unlikely without climate change. Indeed, climate change made the sort of extreme heat felt in France and the Netherlands that summer up to 100 times more likely to occur whilst the record-breaking temperatures in the UK were around 20 times more likely to have occurred. Following record breaking heat that led to the hottest day ever recorded in Australia, Dr Sophie Lewis, a climate scientist at the University of New South Wales, said “It’s not just the frequency that we’re breaking them [temperature records], it’s the margin… We’re now seeing temperatures that are occurring outside what we’d expect from natural variability alone”.
As of July 2020, January 2020 was the warmest January ever recorded in Europe, and Siberia faced a record breaking heatwave, made some 600 times more likely due to climate change, which saw temperatures as high as 38°C in the Arctic Circle. We have just seen the hottest May ever recorded and we now have an 85% chance that 2020 will be the hottest year on record.
What is of particular concern is that the heatwaves hitting Europe have been even more frequent and severe than climate models have predicted. Experts say that Europe and the eastern Mediterranean appear more vulnerable to hotter temperatures than Africa and Southeast Asia, largely because so many older people (who are particularly at risk from increasing temperatures) live in cities which trap heat and can therefore be hotter than surrounding areas.
It is not just human health but also infrastructure that suffers under increased heating. Alex Hynes, Managing Director of Scotland’s railway, warned “Britain’s railways can no longer cope with the effects of the climate crisis.”
Longer and harsher droughts
“An estimated 3.6 billion people (nearly half the global population) already live in areas that are potentially water-scarce at least one month per year.”United Nations world water development report, 2018
Warmer air is able to hold more water vapour. This means that in areas where the air is already dry, global heating makes it even less likely that water vapour in the air will condense to form clouds, resulting in reductions in rainfall and increasing the chance of droughts. To make matters worse, drier soils caused by increased temperatures exacerbate the impacts of reduced rainfall, leading to longer and deeper droughts – with major impacts on global food production and water availability (see sections on impacts on food production and water availability).
It has been proposed that the severe drought experienced by Syria between 2007-2010, made more likely by global heating, was a key factor that contributed to the outbreak of civil war which started in 2011.
The Western US has been crippled by droughts in recent years. The “exceptional” drought in California between 2010-2014 was made much more likely by climate change.
In 2015 a drought in Southern Africa, made up to three times more likely by climate change, reduced agricultural outputs by 15%, whilst in 2017 a drought in East Africa – made up to twice as likely by climate change – displaced around 800,000 people in Somalia. In 2018 an intense drought in Cape Town, made three times more likely by climate change, led to severe water restrictions being put in place and the city came to within days of turning off its water supply: dubbed ‘Day Zero’. It has been calculated that climate change made the chance of a drought this severe go from a “once in 300 years” event to a “once in 100 years” event.
In 2019, Australia’s Murray-Darling basin saw its most severe drought in 120 years of records and Tasmania had the driest January in 120 years, whilst parts of Zimbabwe had the lowest rainfall since 1981, contributing to making more than 5.5 million people at risk of extreme food insecurity. India experienced a harsh drought followed by a searing heatwave, with Chennai being left nearly out of water as its reservoirs ran dry. Global heating has also been directly linked to the “megadrought” that’s currently gripping the South West United States, the worst in over 500 years.
More forest fires
“What climate change does is exacerbate the conditions in which the bushfires happen.”Dr Imran Ahmed, climate scientist at the Australian National University
The hot, dry conditions produced as a result of climate change also increase the chance of – and spread of – forest fires. Indeed, hotter years have been shown to have more fires and the 2019 Lancet Countdown report found that human exposure to wildfires has doubled since 2000. Wildfires can also dramatically increase air pollution – see section on how we are polluting our air.
Wildfires are Earth’s greatest natural disturbance affecting an area the size of India every year. Large forest fires in the western United States have become five times more frequent since the 1970s and 80s, scorching over six times as much land, and lasting almost five times as long.
Indeed, recent years have seen record-breaking wildfires take hold across the globe. The UK saw a record breaking number of fires in 2019 leading scientists to conclude that climate change “has already led to increasing wildfire risk”. This included the Saddleworth moor fire, which burned during the UK’s warmest winter day on record.
In 2016, the Fort McMurray Fire in Canada, estimated to have been made up to six times more likely by climate change, burnt through 1.5 million acres of forest, burned 2,400 homes and buildings and caused 80,000 people to flee their homes – resulting in $10 billion in damage. The devastating recent bushfires in Australia are now estimated to have burnt 20% of Australia’s forest cover, destroyed more than 1,500 homes and killed over 1 billion animals. Experts had been warning for years that a hotter, drier climate would contribute to bushfires becoming more frequent and more intense.
Wildfires have also decimated more than 52,000 square miles of Arctic forest in Siberia, with 11,000 square miles destroyed in just 3 months, making it the largest wildfire disaster in the history of Russia. Other huge areas of the Arctic caught fire too, from eastern Siberia to Greenland to Alaska, with more than 4,000 square miles of forest burned in Alaska. Thomas Smith, an Assistant Professor in Environmental Geography at the London School of Economics, told USA Today: “These are some of the biggest fires on the planet, with a few appearing to be larger than 380 square miles.”
To make matters worse, these Arctic fires are having huge knock-on effects on global warming. Smith said: “The fires are burning through long-term carbon stores (peat soil) emitting greenhouse gases, which will further exacerbate greenhouse warming, leading to more fires.”
More extreme storms and floods
“There’s this remarkable building of this body of evidence that we’re making these storms more deleterious.”Dr. James Kossin, Atmospheric Research Scientist, National Oceanic and Atmospheric Administration
As global temperatures rise, warmer air and warmer seas result in an increase in the amount of water evaporating from the oceans. Warmer air is also able to hold more water vapour – its capacity increasing by 7% for each additional 1°C of heating. The resulting excess of water vapour in the air means that when the air eventually cools down enough for clouds to form, not only will there be more frequent rainfall than usual but there’s also a greater chance that downpours will be heavier. This results in more extreme rainfall, storms and floods, with major impacts on food production. Indeed, 18% of extreme rainfall events are directly attributable to the heating we have already seen.
For example, extreme rainfall is increasing across the United States – in the North East the number of downpours have increased by a whopping 71% since the 1950s. This increase in rainfall is leading to worse flooding in many areas. Following the wettest 12 consecutive months in US history there were major floods in the Midwest: the Mississippi river saw high water in every sub-basin, with one town seeing over 200 consecutive days of flooding. The flooding massively delayed planting and suppressed yields for soy and corn across the region, prompting a plant biologist from the University of Illinois to state “we are living climate change right now.”
In 2020 we have already seen more record breaking flooding around the world. At the beginning of the year 175,000 people were displaced in Jakarta following its most intense rains on record. Japan’s Kyushu region also experienced record breaking rainfall, with over 100 mm of rain falling in an hour. Over one million people were evacuated and thousands of properties were destroyed. Parts of China have also seen their worst rainfall since records began, with 40 million people affected as 33 rivers rose to their highest levels in history resulting in major flooding along the Yangtze, inflicting billions of dollars worth of damages.
Studies show that climate change has increased the extent and frequency of flooding in the UK and other parts of northern Europe too – particularly in parts of Northern and Western Britain. Indeed, the UK Met Office reports that climate change is causing heavy rainfall events to be getting more frequent in the UK. Extended periods of extreme winter rainfall in the UK, similar to those seen in winter 2013-14, are now about seven times more likely due to human-induced climate change and the heavy rains associated with Storm Desmond, an extratropical cyclone that hit the UK, Ireland and parts of Northern Europe in 2015, were made about 60% more likely due to human-induced climate change.
The UK saw extreme flooding in February 2020, with the Met Office declaring that it was the wettest February on record. Three storms battered the UK with weeks of heavy rain and gales of up to 70 mph and the Environment Agency was forced to declare a record 594 simultaneous flood warnings across England. Some regions received over 400% of their previously normal rainfall, and in East Yorkshire 78 homes and businesses experienced severe flooding, with some homes left almost completely underwater. In Wales, a month’s worth of rain fell in 48 hours and the flooding of the River Wye was over half a metre bigger than anything seen for 110 years. The Environment Agency warned that people in the UK need to brace themselves for “more frequent periods of extreme weather like this” because of climate change.
The record-breakingly wet February had followed a series of record floods across the UK the previous November, when several areas in Yorkshire and Derbyshire were struck by a month’s worth of rain in a single day and the river Don reached record levels, with some villages hit by their third “once-in-a-lifetime” deluge in the past 20 years. More than 500 homes were flooded and more than 1,000 properties were evacuated.
Dr John Marsham, a climate change researcher at the University of Leeds and the National Centre for Atmospheric Science, told the Yorkshire Evening Post that the extreme weather is proof of a climate emergency. He said: “It is exactly what we expect from our climate change research, the UK is getting hotter and you can see that in the Met Office report. We’re headed towards catastrophic damage. It’s going to get worse and we have to adapt quickly. What we do in the next 10 years is critical to avoid catastrophic climate change.”
To make matters worse, nearly half of the world’s coastal wetlands, which usually provide natural protection from storm surge flooding (as well as being important stores of carbon), have been lost over the last 100 years – due to sea level rises, global heating, human activity, and extreme weather events. Indeed, areas with more wetland coverage experience significantly less property damage from storms and floods (see section on wetlands).
Aside from the direct impacts on people’s lives, homes and businesses, flooding can also cause hazardous chemicals from old mines, industrial sites and sewage works to be swept up and dumped into rivers and onto farmland, posing a major threat to human health and ecosystems. After floods in the UK in 2012, levels of lead were much higher in rivers and were sufficient to kill farm animals grazing on the land. Following the floods resulting from Hurricane Harvey, there were several incidents of leaks at toxic waste sites around Houston, and a new report found around 2000 similar sites near the coast of the US are in danger of being flooded. This will be a big issue with flooding in the future.
Storms and floods also have huge economic impacts, and some insurance companies are already warning that they will soon stop insuring basements in London, New York and Mumbai.
The UK Environment Agency estimated that the floods in England in 2007 cost £3.2 billion and that the cost of winter floods across the UK in 2015 were around £1.6 billion, with insurance policies of many of those worst hit not covering the full losses. The clean-up bill following the storms in the UK in February 2020 is set to top £360 million, with the average household claiming £36,000 on insurance. The UK National Audit Office estimates that for every £1 spent on protecting communities from flooding, around £9 in property damages and wider impacts can be avoided.
“Unrestrained climate change means we will see many more [Hurricane] Harveys in the future.”Professor Michael Mann, Director of the Pennsylvania State Earth System Science Centre
Rising temperatures are causing a supercharging of hurricanes, whereby hurricanes become more intense, produce more rainfall and cause higher storm surges – increasing the risk of major damage from such events. Indeed, the proportion of tropical storms that have rapidly strengthened into powerful hurricanes has tripled over the past 30 years. Tropical storms are also being diverted away from their usual tracks, meaning more coastal cities are now in their path.
In recent years we have seen a series of extremely powerful storms, including Hurricane Patricia in 2018 – the strongest storm on record with sustained winds over 200 mph. Indeed, of the seven cyclone regions studied by scientists, since 2013, five have had the strongest storm on record – which would be extremely unlikely just by chance.
One of these storms was Typhoon Haiyan, which struck the Philippines and killed 8,000 and displaced 4 million people due to a massive 20-30 foot storm surge. The ocean temperatures in the Western North Pacific had increased dramatically in recent years, at least in part due to global heating, providing more favourable conditions for the formation of such incredibly powerful storms.
Hurricane Harvey is estimated to have displaced 30,000 people and caused up to $125 billion dollars worth of damages, making it one of the costliest tropical storms to ever strike the United States. Harvey broke records for the most rainfall ever from a single storm in the US, with some parts of Housten receiving over 1.5 m of rainfall. It’s been calculated that 20 trillion gallons of water fell over East Texas. Scientists studying the event concluded that climate change made the rainfall about 8-19% more intense, or, to put it another way, three quarters of the economic damages due to the intense rainfall were attributable to human caused climate change.
Just weeks after Harvey struck Texas, Maria, the strongest storm of 2017 (a category 5 hurricane), devastated the caribbean including the islands of Dominica, St Croix and Puerto Rico and killed 2,900 people. It is estimated to be the third costliest storm on record (next to Harvey and Katrina). Scientists who have studied this storm also say that climate change increased the likelihood of the record breaking extreme rainfall of this storm by nearly a factor of five.
In 2019, cyclone Idai struck Mozambique, Zimbabwe and Malawi. Over 600,000 people were displaced. In the city of Beira alone nearly 80% of homes and public infrastructure were destroyed and a cholera outbreak followed in the storm’s wake. The huge destruction caused by cyclone Idai makes it the costliest tropical cyclone ever in the South-West Indian Ocean basin. When asked whether Idai was linked to global heating, Dr Friederike Otto of Oxford University, said “There are three factors with storms like this: rainfall, storm surge and wind. Rainfall levels are on the increase because of climate change, and storm surges are more severe because of sea level rises.”
Hurricane damage is exacerbated by losses in wetlands. Indeed, recent wetland losses are estimated to have increased the property damage from Hurricane Irma in 2017 by $430 million.
What is global heating doing to our oceans, coastlines and wildlife?
Melting ice and rising seas
“Sea level is rising much faster and Arctic sea ice cover shrinking more rapidly than we previously expected. Unfortunately, the data now show us that we have underestimated the climate crisis in the past.”Stefan Rahmstorf, Professor of Physics of the Oceans, Potsdam University
As atmospheric conditions get hotter, the water in our oceans heats up too. Indeed, over 90% of the increased heat trapped in our atmosphere is being stored in the oceans. In 2019, the heat in the world’s oceans reached a new record level, confirming “irrefutable and accelerating” heating of the planet. It has been calculated that the heat energy being absorbed by the oceans is the equivalent of between 3 to 6 Hiroshima-size atomic bombs every second.
All this this extra heat causes the water to expand and take up more space, resulting in rises in sea levels.
Changes in global temperatures since 1880
Changes in global sea levels since 1880
In addition, hotter water in our oceans, along with hotter air in our atmosphere, leads to the melting of sea ice, ice sheets and mountain glaciers. Fortunately, when sea ice melts it doesn’t affect sea levels – just like how an ice cube melting in a glass of water doesn’t cause the water level to go up. However, when land-based ice sheets and glaciers melt, the water runs off into the sea, causing sea levels to rise – just like what would happen if you added another ice cube to the glass of water and waited for it to melt.
In the Arctic, the area covered by sea ice in the summer has shrunk by 40% since 1979 and is now declining at a rate of 12.8% per decade. Compared to the average sea ice cover between 1981 and 2010, we have now lost about two million square km of ice – that’s an area larger than Alaska and California combined. As of July 2020 the sea ice was yet again at a record low for the time of year, and this year may break the record for lowest annual minimum previously set in 2012. Arctic sea ice is what polar bears use to hunt seals on, so they are now being forced to forage on land where they have difficulty in finding prey. Dr Steve Amstrup, chief scientist at conservation organisation Polar Bears International warned: “If we allow the sea ice loss to continue, all the polar bears will soon be gone.”
The Greenland ice sheet, the second largest in the world, is losing ice seven times faster than in the 1990s, whilst the Antarctic ice sheet has lost three trillion tonnes of ice in the past 25 years and is now losing 252 billion tonnes a year – that’s six times more than it was 30 years ago.
Overall, over the past 40 years the amount of ice we have lost from our planet averages out to the loss of around 300 double-decker-sized chunks of ice… EVERY SECOND.
What’s even more concerning is the fact that the scale and speed of ice sheet loss is faster than models have predicted, threatening inundation for hundreds of millions of people. The Antarctic ice sheet is losing mass at an accelerating pace and it is thought that some regions may be reaching a tipping point, potentially leading to rates of sea level rise at least an order of magnitude larger than those observed now.
Dr. Louise Sime, Climate Scientist at the British Antarctic Survey, said: “This finding should be of huge concern for all those who will be affected by sea level rise. If this very high rate of ice loss continues, it is possible that new tipping points may be breached sooner than we previously thought.”
The ‘fast melting’ part of the ice sheet is already showing signs of an “unstoppable and irreversible” collapse which would lock in around one metre of sea level rise. Indeed, in January 2020, scientists revealed that a massive sheet of ice in the Thwaites Glacier in West Antarctica, known as the “doomsday glacier”, is melting far faster than experts had previously thought, with “huge implications” for global sea level rise. David Holland, Professor of Atmosphere and Ocean Science at NYU, said: “That is really, really bad. That’s not a sustainable situation for that glacier.”
Our glaciers are melting too. Melting glaciers are not only responsible for about a third of our observed sea level rise, but mountain glaciers also store up water and release it in the dry season, making them an important source of water in mountain areas. Indeed, drainage basins from glaciated mountain ranges cover 26% of the global land surface (outside of Greenland and Antarctica), and are lived in by almost one-third of the world’s population. There are currently about 1.9 billion people across the globe living downstream of mountain glaciers, depending on water from these glaciers for irrigation, hydropower, domestic consumption and industry and who would be negatively affected by their loss.
In 2018, the World Glacier Monitoring Service reported the 30th consecutive year that global glaciers had lost mass. The European Alps have lost over a billion tonnes of ice since the year 2000 and are continuing to lose 1.2% of their mass every year. A study of the Himalayas found that glaciers there are now melting twice as fast as they were between 1975 and 2000 and are losing 8 billion tonnes of ice a year – that’s the equivalent to 3.2 million Olympic-sized swimming pools.
The Andes are estimated to be losing an even more alarming 23 billion tonnes of ice each year, with glaciers in the tropical Andes having already shrunk by 30-50% since 1970. For example, the glaciers of Bolivia shrank by 43% between 1986 and 2014. Researchers point out that these dwindling glaciers are estimated to “provide 20% to 28% of water for El Alto and La Paz. Therefore glacier loss will have a considerable impact, which will be felt particularly during the dry season, when glacial water provides the majority of urban water. The glaciers and mountain water systems also support agriculture, power generation and natural ecosystems throughout the region.”
Loss of homes due to rising seas
“The shock for us was that tidal flooding could become the new normal in the next 15 years; we didn’t think it would be so soon… If you live on a coast and haven’t seen coastal flooding yet, just give it a few years. You will.”Dr. Melanie Fitzpatrick, climate scientist with the Union of Concerned Scientists’ Climate Program
“[The impacts of tidal flooding] are happening and will be devastating for coastal communities.”Andrew Shepherd, Professor of Earth Observation at the University of Leeds
Rising seas are already displacing hundreds of thousands of people from vulnerable coastal areas in the South Pacific, Indonesia and Bangladesh, and climate displacement is already well underway in places such as Vietnam. Over the past six decades, much of the Isle de Jean Charles, Louisiana – once home to 400 people – has disappeared due to subsidence caused by oil and gas extraction and now rising sea levels. In November 2019 it was reported that five whole Pacific Islands – part of the Solomon Islands – have now been entirely lost to rising sea levels, with a further six having large parts of their coastline eroded, destroying entire villages.
As a result of a combination of subsidence and rising sea levels, a storm that hit Venice in 2019 caused the worst floods in 50 years and left Saint Mark’s Square submerged under more than one metre of water. Saint Mark’s Basilica has only flooded six times in the past in 1,200 years – four of these floods were in the last 20 years, with the last one only one year before.
Many coastal cities in the United States are now seeing ‘nuisance flooding’ at high tide closing roads, blocking drains and damaging infrastructure. According to the National Oceanic and Atmospheric Organization such flooding has already “increased in the U.S. on average by about 50 percent since 20 years ago and 100 percent since 30 years ago.” Experts say that, for those living in coastal areas, tidal flooding could become the new normal in the next 15 years.
Impacts of heating on ocean life
“Unless we take evasive action, our future oceans will have fewer fish, fewer whales and frequent dramatic shifts in ecological structure will occur, with concerning implications for humans who depend on the ocean.”Dr Éva Plagányi at the Commonwealth Scientific and Industrial Research Organisation, Australia
Scientists have warned that marine heatwaves are sweeping oceans “like wildfires”, with extreme temperatures killing swathes of sea-life and destroying crucial species that provide shelter and food to many others – such as seagrass, kelp and corals. In fact, due to the slow response of the oceans to atmospheric heating, we have already locked in a large future increase in marine heatwaves.
Repeated heat stress has now caused nearly half of the world’s corals to bleach and then die. Tropical coral reefs are some of the most important and diverse ecosystems on the planet, which support up to one million other species and provide food, protection from storms and livelihoods for nearly one billion people.
As Michael Mann, Professor of Atmospheric Science at Pennsylvania State University, put it: “Our generation is going to be responsible for the loss of one of the most majestic ecosystems on the face of the Earth. We’re literally watching the death of this natural wonder.”
Ocean warming not only damages sea life directly, but also causes the oxygen that is usually dissolved in seawater to become less soluble. This leads to areas of water with depleted levels of oxygen, which can lead to suffocation of the sea creatures living within them. The runoff of nutrients from agriculture and sewage further exacerbates oxygen decline in coastal waters through causing the overgrowth of algae. This ‘algal bloom’ blocks sunlight from reaching submerged plants, which die and are fed off by bacteria that use up the oxygen in the water – a process known as eutrophication.
Indeed, in the last 70 years, low-oxygen ocean zones have grown by more than 4.5 million square km – an area roughly as large as the entire European Union – whilst the number of ocean ‘dead zones’ (areas with exceedingly low oxygen) has increased by a factor of 10.
Impacts of carbon dioxide on ocean life
Another impact of increasing greenhouse gas emissions on our oceans is that excess carbon dioxide in our atmosphere dissolves in seawater, making it more acidic. Indeed, more than one third of the carbon dioxide in our atmosphere is absorbed by seawater. Increases in acidity affect marine life, from shellfish like clams and oysters to whole coral reef communities, by removing minerals that they require in order to grow their shells and skeletons. This has knock-on effects on the survival and abundance of a wide variety of species.
The oceans are now 30% more acidic relative to the beginning of the industrial era, making them more acidic than any time in the last 65 million years. Today, ocean acidification is occurring approximately ten times faster than anything experienced during the last 300 million years – jeopardising the ability of ocean systems to adapt.
Impacts of heating on land-based wildlife
“Personally I find the results alarming. Species attempt to adapt to changing environment, but they cannot do it at a sufficient pace to ensure that populations are viable. Climate change has caused irreversible damage to our biodiversity already, as evidenced by the findings of this study. The fact that species struggle to adapt to the current rate of climate change means we have to take action immediately in order to at least halt or decrease the rate.”Viktoriia Radchuk, Leibniz Institute for Zoo and Wildlife Research in Germany
Land-based creatures are extremely sensitive to changes in climate. This is because, over millions of years, wild species have evolved to have finely tuned adaptations that allow them to live in the specific climate of their local environment. For example, many are adapted to live at certain temperatures and with certain amounts of rainfall – and are also very sensitive to changes in the daily and seasonal variation in these factors. In fact, the local climate is the primary factor that controls where species live.
What this means is that when the climate changes at any particular location in the world, it has direct and powerful impacts on the local creatures.
We are already seeing many devastating and direct effects of climate change on wildlife, for example, trees dying through insufficient water and animals losing their ability to forage for food because of heat stress – leading to local extinctions.
We are also seeing impacts due to changes in the timings of the seasons, such as the early springs that we are experiencing in some parts of the world (which have become a feature on The News). The problem is, such changes in seasonality are experienced unequally by different species, which leads to mismatches in the timing of important life events for animals and plants. For example,pollinating insects are coming out of hibernation before flowers emerge, and the migration of birds is out of synchrony with peaks in abundance of their prey, leading to poor reproduction and death.
In addition, as weather extremes increase in intensity and frequency due to climate change, wild plants and animals are suffering from events such as droughts, wildfires, and floods. These events alone are pushing some species towards extinction. The intense Australian bushfires of early 2020 have destroyed the habitats of many species, with at least 50 rare animals and plants having had over four fifths of their habitat areas affected. It has been estimated that over 1 billion animals were also killed, and it is feared that this, in combination with loss of habitats, will lead to local extinctions of species like the koala.
Given that today’s climate is changing so fast that there is no time for creatures to adapt, often the only option for species is to try to move– in order to look for new areas that have a suitable climate for them to live in. This may sound straightforward, but, in a rapidly changing climate, species have to shift their ranges remarkably fast. Even amongst land mammals, which are much more mobile than plants or insects, it is estimated that, at best, 30% of species will not be able to shift fast enough to keep up with climate change. While some species are indeed starting to shift their ranges, this is generally taking place slower than the climate is changing – and there are many species that are not shifting, or that are only shifting only very slowly.
An additional challenge to creatures being able to shift location is that creatures within an ecosystem need to have the very specific species that they interact living alongside them. For example, plants rely on their pollinators, predators on their prey, and herbivores on the plants they eat. So if different creatures in an ecosystem are not able to shift at the same rate, ecological communities will become unstable.
To make matters worse, even if species were to be able to move, many of the cooler or more sheltered places on Earth (that creatures could use to take refuge from increasing temperatures) have now been degraded, fragmented or colonised by human activities.
Plus, there are those animals that require conditions of extreme cold for their survival. As global temperatures rise rapidly, there is nowhere on Earth for them to escape to. For example, polar bears usually stand on floating blocks of sea ice when they’re out hunting for seals in the freezing Northern seas. However, due to rising temperatures sea ice is rapidly melting so they are now forced to walk or swim enormous distances to get to any remaining ice, or to forage for food on land where they have difficulty in finding prey. Some bears have resorted to travelling south and scavenging for food in places where humans live. In February 2019, 50 polar bears invaded the remote Russian town of Belushya Guba. Videos posted on social media showed the scrawny starving creatures picking their way through rubbish bins, rummaging through dumps and even roaming around inside buildings. Sea ice and land-based ice sheets are also critical for organisms such as whales, seals, and sea birds.
Land-based wildlife is not only being enormously impacted by climate change, but also by land degradation, deforestation, pollution and over-consumption. For lots more information on the devastating impacts that humans are already having on wildlife, see section on how we are destroying our wildlife.