How rising temperatures affect our health



The first half of 2019 is the equal hottest on record and summer is set to be a scorcher.
Chayathorn Lertpanyaroj/Shutterstock

Liz Hanna, Australian National University

This story is part of Covering Climate Now, a global collaboration of more than 250 news outlets to strengthen coverage of the climate story.

Global warming is accelerating, driven by the continuing rise in greenhouse gas emissions. Australia’s climate has warmed by just over 1°C since 1910, with global temperatures on course for a 3-5°C rise this century.

Australia is ahead of the global temperature curve. Our average daily temperature is 21.8°C – that’s 13.7°C warmer than the global average of 8.1°C.

Heat extremes (days above 35°C and nights above 20°C) are now more frequent in Australia, occurring around 12% of the time compared to around 2% of the time between 1951 and 1980.

So what do high temperatures do to our bodies? And how much extra heat can people and our way of living tolerate?

More scorchers ahead

Australia’s summer of 2018-19 was 2.14°C warmer than the 1961–90 average, breaking the previous record set in 2012–13 by a large margin. It included an unprecedented sequence of five consecutive days with nationally averaged maximum temperatures above 40°C.




Read more:
The reality of living with 50℃ temperatures in our major cities


The first half of 2019 ranks as the equal second hottest since records began for the world, and also Australia.

The Bureau of Meteorology (BOM) has warned this summer will be another scorcher. Hot dry northerly winds tracking across drought-affected New South Wales and Queensland have the capacity to deliver blistering heat and extreme fire risks to the southern states, and little relief is in sight for those in drought.

Some rural Australians have already been exposed to 50°C days, and the major southern metro cities are set to do the same within the next decade or so.

How our bodies regulate heat

Like most mammals and birds, humans are endotherms (warm-blooded), meaning our optimal internal operating temperature (approximately 36.8°C +/− 0.5) is minimally influenced by ambient temperatures.

Quietly sitting indoors with the air temperature about 22°C, we passively generate that additional 15°C to keep our core temperature at about 37°C.

Even when the air temperature is 37°C, our metabolism continues to generate additional heat. This excess internal heat is shed into the environment through the evaporation of sweat from our skin.

Our optimal internal body temperature is 36.8°C.
Slaohome/Shutterstock

Temperature and humidity gradients between the skin surface and boundary layer of air determine the rate of heat exchange.

When the surrounding air is hot and humid, heat loss is slow, we store heat, and our temperatures rises.

That’s why hot, dry air is better tolerated than tropical, humid heat: dry air readily absorbs sweat.

A breeze appears refreshing by dislodging the boundary layer of saturated air in contact with the skin and allowing in drier air – thus speeding up evaporation and heat shedding.

What happens when we overheat?

Heat exposure becomes potentially lethal when the human body cannot lose sufficient heat to maintain a safe core temperature.

When our core temperature reaches 38.5°C, most would feel fatigued. And the cascade of symptoms escalate as the core temperature continues to rise beyond the safe functioning range for our critical organs: the heart, brain and kidneys.

Much like an egg in a microwave, protein within our body changes when exposed to heat.




Read more:
How heat can make your body melt down from the inside out


While some heat-acclimatised elite athletes, such as Tour de France cyclists, may tolerate 40°C for limited periods, this temperature is potentially lethal for most people.

As a pump, the heart’s role is to maintain an effective blood pressure. It fills the hot and dilated blood vessels throughout the body to get blood to vital organs.

Exposure to extreme heat places significant additional workload on the heart. It must increase the force of each contraction and the rate of contractions per minute (your heart rate).

If muscles are also working, they also need an increased blood flow.

If all this occurs at a time when profuse sweating has led to dehydration, and therefore lower blood volume, the heart must massively increase its work.

Dry air readily absorbs sweat, whereas humid air doesn’t, making it less tolerable.
Cliplab/Shutterstock

The heart is also a muscle, so it too needs extra blood supply when working hard. But when pumping hard and fast and its own demand for blood flow is not matched by its supply, it can fail. Many heat deaths are recorded as heart attacks.

High aerobic fitness levels offer some heat protection, yet athletes and fit young adults pushing themselves too hard also die in the heat.

Who is more at risk?

Older Australians are more vulnerable to heat stress. Age is commonly associated with poorer aerobic fitness and impaired ability to detect thirst and overheating.




Read more:
To keep heatwaves at bay, aged care residents deserve better quality homes


Obesity also increases this vulnerability. Fat acts as an insulating layer, as well as giving the heart a more extensive network of blood vessels to fill. The additional weight requires increased heat-generating muscular effort to move.

Certain medications can lower heat tolerance by interfering with our natural mechanisms necessary to cope with the heat. These include drugs that limit increases in heart rate, lower blood pressure by relaxing blood vessels, or interfere with sweating.

Core temperatures are increased by about half a degree during late stage pregnancy due to hormonal responses and increased metabolic rate. The growing foetus and placenta also demand additional blood flow. Exposure of the fetus to heat extremes can precipitate preterm birth and life-long health problems such as congential heart defects.

Won’t we just acclimatise?

Our bodies can acclimatise to hot temperatures, but this process has its limits. Some temperatures are simply too hot for the heart to cope with and for sweat rates to provide effective cooling, especially if we need to move or exercise.

We’re also limited by our kidneys’ capacity to conserve water and electrolytes, and the upper limit to the amount of water the human gut can absorb.

Profuse sweating leads to fluid and electrolyte deficits and the resulting electrolyte imbalance can interfere with the heart rhythm.

Mass death events are now occurring during heat waves in traditionally hot countries such as India and Pakistan. This is when heat extremes approaching 50°C exceed the human body’s capacity to maintain its safe core temperature range.




Read more:
Could we acclimatise to the hotter summers to come?


Heatwaves are hotter, more frequent and lasting longer. We can’t live life entirely indoors with air conditioning as we need to venture outdoors to commute, work, shop, and care for the vulnerable. People, animals and our social systems depend on this.

Besides, on a 50°C day, air conditioning units will struggle to remove 25°C from the ambient air.The Conversation

Liz Hanna, Honorary Senior Fellow, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Why hot weather records continue to tumble worldwide


Andrew King, University of Melbourne

It sometimes feels like we get a lot of “record-breaking” weather. Whether it’s a heatwave in Europe or the “Angry Summer” in Australia, the past few years have seen temperature records tumble.

This is the case both locally – Sydney had its hottest year on record in 2016 – and globally, with the world’s hottest year in 2016 beating the record set only the year before.

Some of 2016’s heat was due to the strong El Niño. But much of it can be linked to climate change too.

We’re seeing more heat records and fewer cold records. In Australia there have been 12 times as many hot records as cold ones in the first 15 years of this century.

If we were living in a world without climate change, we would expect temperature records to be broken less often as the observational record grows longer. After all, if you only have five previous observations for annual temperatures then a record year isn’t too surprising, but after 100 years a new record is more notable.

In contrast, what we are seeing in the real world is more hot temperature records over time, rather than less. So if you think we’re seeing more record-breaking weather than we should, you’re right.

Why it’s happening

In my new open-access study published in the journal Earth’s Future, I outline a method for evaluating changes in the rate at which temperature records are being broken. I also use it to quantify the role of the human influence in this change.

To do it, I used climate models that represent the past and current climate with both human influences (greenhouse gas and aerosol emissions) and natural influences (solar and volcanic effects). I then compared these with models containing natural influences only.

Lots of hot records, fewer cold ones

Taking the example of global annual temperature records, we see far more record hot years in the models that include the human influences on the climate than in the ones without.

Crucially, only the models that include human influences can recreate the pattern of hot temperature records that were observed in reality over the past century or so.

Observed and model-simulated numbers of hot and cold global annual temperature records for 1861-2005. Observed numbers of record occurrences are shown as black circles with the model-simulated record numbers under human and natural influences (red box and whiskers) and natural influences only (orange box and whiskers) also shown. The central lines in the boxes represent the median; the boxes represent interquartile range.
Author provided

In contrast, when we look at cold records we don’t see the same difference. This is mainly because cold records were more likely to be broken early in the temperature series when there were fewer previous data. The earliest weather data comes from the late 19th century, when there was only a weak human effect on the climate relative to today. This means that there is less difference between my two groups of models.

In the models that include human influences on the climate, we see an increase in the number of global record hot years from the late 20th century onwards, whereas this increase isn’t seen in the model simulations without human influences. Major volcanic eruptions reduce the likelihood of record hot years globally in both groups of model simulations.

Projecting forward to 2100 under continued high greenhouse gas emissions, we see the chance of new global records continuing to rise, so that one in every two years, on average, would be a record-breaker.

Chance of record hot global annual temperatures in climate models with human and natural influences (red) and natural influences only (orange). Grey curve shows the statistical likelihood of a new hot record each year (100% in the first year, 50% in the second year, 33% in the third year, and so on). Grey vertical bars show the timing of major volcanic eruptions through the late-19th and 20th centuries.
Author provided

I also looked at specific events and how much climate change has increased the likelihood of a record being broken.

I used the examples of the record hot years of 2016 globally and 2014 in Central England. Both records were preceded by well over a century of temperature observations, so in a non-changing climate we would expect the chance of a record-breaking year to be less than 1%.

Instead, I found that the chance of setting a new record was increased by at least a factor of 30 relative to a stationary climate, for each of these records. This increased likelihood of record-breaking can be attributed to the human influence on the climate.

More records to come?

The fact that we’re setting so many new hot records, despite our lengthening observation record, is an indicator of climate change and it should be a concern to all of us.

The ConversationThe increased rate at which we are getting record hot temperatures is controlled by the speed of global warming, among other factors. To meet the Paris target of keeping global warming below 2℃ we will have to reduce our greenhouse gas emissions drastically. Besides keeping average global temperatures under control, this would also reduce the chance of temperature records continuing to tumble, both globally and locally.

Andrew King, Climate Extremes Research Fellow, University of Melbourne

This article was originally published on The Conversation. Read the original article.

Australia’s record-breaking winter warmth linked to climate change


File 20170901 27714 7nsuln
This winter had some extreme low and high temperatures.
Daniel Lee/Flickr, CC BY-NC

Andrew King, University of Melbourne

On the first day of spring, it’s time to take stock of the winter that was. It may have felt cold, but Australia’s winter had the highest average daytime temperatures on record. It was also the driest in 15 years.

Back at the start of winter the Bureau of Meteorology forecast a warm, dry season. That proved accurate, as winter has turned out both warmer and drier than average.


Read more: Australia’s dry June is a sign of what’s to come


While we haven’t seen anything close to the weather extremes experienced in other parts of the world, including devastating rainfalls in Niger, the southern US and the Indian subcontinent all in the past week, we have seen a few interesting weather extremes over the past few months across Australia.

Much of the country had drier conditions than average, especially in the southeast and the west.
Bureau of Meteorology

Drier weather than normal has led to warmer days and cooler nights, resulting in some extreme temperatures. These include night-time lows falling below -10℃ in the Victorian Alps and -8℃ in Canberra (the coldest nights for those locations since 1974 and 1971, respectively), alongside daytime highs of above 32℃ in Coffs Harbour and 30℃ on the Sunshine Coast.

During the early part of the winter the southern part of the country remained dry as record high pressure over the continent kept cold fronts at bay. Since then we’ve seen more wet weather for our southern capitals and some impressive snow totals for the ski fields, even if the snow was late to arrive.

This warm, dry winter is laying the groundwork for dangerous fire conditions in spring and summer. We have already had early-season fires on the east coast and there are likely to be more to come.

Climate change and record warmth

Australia’s average daytime maximum temperatures were the highest on record for this winter, beating the previous record set in 2009 by 0.3℃. This means Australia has set new seasonal highs for maximum temperatures a remarkable ten times so far this century (across summer, autumn, winter and spring). The increased frequency of heat records in Australia has already been linked to climate change.

Winter 2017 stands out as having the warmest average daytime temperatures by a large margin.
Bureau of Meteorology

The record winter warmth is part of a long-term upward trend in Australian winter temperatures. This prompts the question: how much has human-caused climate change altered the likelihood of extremely warm winters in Australia?

I used a standard event attribution methodology to estimate the role of climate change in this event.

I took the same simulations that the Intergovernmental Panel on Climate Change (IPCC) uses in its assessments of the changing climate, and I put them into two sets: one that represents the climate of today (including the effects of greenhouse gas emissions) and one with simulations representing an alternative world that excludes our influences on the climate.

I used 14 climate models in total, giving me hundreds of years in each of my two groups to study Australian winter temperatures. I then compared the likelihood of record warm winter temperatures like 2017 in those different groups. You can find more details of my method here.

I found a stark difference in the chance of record warm winters across Australia between these two sets of model simulations. By my calculations there has been at least a 60-fold increase in the likelihood of a record warm winter that can be attributed to human-caused climate change. The human influence on the climate has increased Australia’s temperatures during the warmest winters by close to 1℃.

More winter warmth to come

Looking ahead, it’s likely we’re going to see more record warm winters, like we’ve seen this year, as the climate continues to warm.

The likelihood of winter warmth like this year is rising. Best estimate chances are shown with the vertical black lines showing the 90% confidence interval.
Author provided

Under the Paris Agreement, the world’s nations are aiming to limit global warming to below 2℃ above pre-industrial levels, with another more ambitious goal of 1.5℃ as well. These targets are designed to prevent the worst potential impacts of climate change. We are currently at around 1℃ of global warming.

Even if global warming is limited to either of these levels, we would see more winter warmth like 2017. In fact, under the 2℃ target, we would likely see these winters occurring in more than 50% of years. The record-setting heat of today would be roughly the average climate of a 2℃ warmed world.

While many people will have enjoyed the unusual winter warmth, it poses risks for the future. Many farmers are struggling with the lack of reliable rainfall, and bad bushfire conditions are forecast for the coming months. More winters like this in the future will not be welcomed by those who have to deal with the consequences.


Climate data provided by the Bureau of Meteorology. For more details about winter 2017, see the Bureau’s Climate Summaries.

The ConversationYou can find more details on the specific methods applied for this analysis here.

Andrew King, Climate Extremes Research Fellow, University of Melbourne

This article was originally published on The Conversation. Read the original article.

Climate change to blame for Australia’s July heat


Andrew King, University of Melbourne

Winter hasn’t felt too wintry yet in much of Australia. Most of us have have had more sunshine, higher temperatures, and less rainfall than is normal for the time of year. In fact, Australia just had its warmest average daytime maximum temperatures for July since records began in 1910.

This July saw the warmest average maximum temperatures on record across Australia.
Bureau of Meteorology

The north and centre of the continent saw the biggest temperature anomalies as Western Australia, the Northern Territory and Queensland experienced record warm daytime July temperatures. Only the southwestern tip of Western Australia and western Tasmania had slightly below-average daytime temperatures.

Southern Australia was again very dry as the frontal systems that usually bring rain remained further south than usual.


Read more: Winter heatwaves are nice … as extreme weather events go.


For most of us, warm and dry winter conditions are quite pleasant. But with drought starting to rear its head and a severe bushfire season on the cards, some cooler wetter weather would be helpful to farmers and fire services across the country.

What caused the unusual warmth?

Often when we have warmer winter weather in Australia it is linked to El Niño conditions in the Pacific or a positive Indian Ocean Dipole. Both of these Pacific and Indian Ocean patterns tend to shift atmospheric pressure patterns in a way that brings more stable conditions and warmer, drier weather to Australia.

This year, however, neither El Niño nor the Indian Ocean Dipole is playing a role in the warm weather. The sea surface temperature patterns in the Pacific and Indian Oceans are close to average, so neither of these factors is driving Australia’s record warmth.

A clear human fingerprint

Another factor that might have influenced the July heat is human-caused climate change.

To assess the role of climate change in this event, I used climate model simulations and a standard event-attribution method. I first evaluated the climate models to gauge how well they capture the observed temperatures over Australia during July. I then computed the likelihood of unusually warm July average maximum temperatures across Australia in two groups of climate model simulations: one representing the world of today, and another representing a world without human influences on the climate.

I found a very clear signal that human-induced climate change has increased the likelihood of warm July temperatures such as the ones we’ve just experienced. My results suggest that climate change increased the chances of this record July warmth by at least a factor of 12.

July heat is on the rise

I also wanted to know if this kind of unusual July warmth over Australia will become more common in future.

I looked at climate model projections for the next century, and examined the chances of these warm conditions occurring in periods when global warming is at 1.5℃ and 2℃ above pre-industrial levels (we have had roughly 1℃ of global warming above these levels so far).

The 1.5℃ and 2℃ global warming targets were decided in the Paris Agreement, brokered in December 2015. Given that we are aiming to limit global warming to these levels it is vital that we have a good idea of the climate we’re likely to be living in at these levels of warming.

I found that even if we manage to limit global warming to 1.5℃ we can expect to experience such July heat (which is record-breaking by today’s standards) in about 28% of winters. At 2℃ of global warming, the chances of warm July temperatures like 2017 are 43% for any given year.

More Julys like this are on the way as the globe heats up.
Andrew King, Author provided

The ConversationGiven the benefits of fewer and less intense heat extremes over Australia at lower levels of global warming, there is a clear incentive to try and limit climate change as much as possible. If we can reduce our greenhouse gas emissions and hold global warming to the Paris target levels, we should be able to avoid the kind of unusual warmth we have seen this July becoming the new normal.

Andrew King, Climate Extremes Research Fellow, University of Melbourne

This article was originally published on The Conversation. Read the original article.

2015’s record-breaking temperatures will be normal by 2030 – it’s time to adapt


Sophie Lewis, Australian National University

Generation Y has grown up in a rapidly warming world. According to the US National Climate Data Centre, every month since February 1985 has seen above average global temperatures, compared with the twentieth century. I have no memories of a “normal” month.

2016 is on track to be the hottest year on record, surpassing the previous records set in 2015 and in 2014. These are just a few of the flurry of recent record temperatures, which includes Australia’s hottest day, week, month, season and year.

The question now is what the future will look like. At some point in the decades to come, these record-breaking temperatures will not be rare; they will become normal. But when exactly?

In a new study just released in the Bulletin of the American Meteorological Society, I (together with co-authors Andrew King and Sarah Perkins-Kirkpatrick) find that on the current greenhouse gas emissions trajectory, global temperatures like 2015 will by normal by 2030, and Australia’s record-breaking 2013 summer will likely be an average summer by 2035.

While we still have time to delay some of these changes, others are already locked in – cutting emissions will make no difference – so we must also adapt to a warmer world. This should be a sobering thought as world leaders gather in Marrakech to begin work on achieving the Paris Agreement which came into force last week.

Today’s extremes, tomorrow’s normal

The recent record-breaking temperatures have often been described as the “new normal”. For example, after the new global temperature record was set in 2016, these high temperatures were described as a new normal.

What is a new normal for our climate? The term has been used broadly in the media and in scientific literature to make sense of climate change. Put simply, we should get used to extremes temperatures, because our future will be extreme.

But without a precise definition, a new normal is limited and difficult to understand. If 2015 was a new normal for global temperatures, what does it mean if 2017, 2018, or 2019 are cooler?

In our study we defined the new normal as the point in time when at least half the following 20 years are warmer than 2015’s record breaking global temperatures.

We examined extreme temperatures in a number of state-of-the-art climate models from an international scientific initiative. We also explored how different future greenhouse gas emissions impact temperatures.

We used four different greenhouse gas scenarios, known as Representative Concentration Pathways, or RCPs. These range from a business-as-usual situation (RCP8.5) to a major cut to emissions (RCP2.6).

It is worth emphasising that real-world emissions are tracking above those covered by these hypothetical storylines.

2015’s record temperatures will likely become normal between 2020 and 2030.

Future extremes

Our findings were straightforward. 2015’s record-breaking temperatures will be the new normal between 2020 and 2030 according to most of the climate models we analysed. We expect within a decade or so that 2015’s record temperatures will likely be average or cooler than average.

By 2040, 2015’s temperatures were average or cooler than average in 90% of the models. This result was unaffected by reducing greenhouse gas emissions or not – we are already locked in to a significant amount of further warming.

We also looked at the timing of a new normal for different regions. Australia is a canary in the coal mine. While other regions don’t see extreme temperatures become the new normal until later in the century, Australia’s record-breaking 2013 summer temperatures will be normal by 2035 – according to the majority of the models we looked at.

At smaller spatial scales, such as for state-based based temperature extremes, we can likely delay record-breaking temperatures becoming the new normal by committing to significant greenhouse gas cuts. This would clearly reduce the vulnerability of locations to extreme temperatures.

Cutting emissions (top) and business as usual (bottom) makes little difference to the new normal globally.
Author provided

Living in a warmer world

If you like heading to the beach on hot days, warmer Australian summers seem appealing, not alarming.

But Australia’s position as a hot spot of future extremes will have serious consequences. The 2013 summer, dubbed the “angry summer”, was characterised by extreme heatwaves, widespread bushfires and a strain on infrastructure.

Our results suggest that such a summer will be relatively mild within two decades, and the hottest summers will be much more extreme.

My co-authors, Andrew and Sarah, and I all grew up in a world of above-average temperatures, but our future is in a world were our recent record-breaking temperatures will be mild. Our new research shows this is not a world of more pleasantly hot summer days, but instead of increasingly severe temperature extremes.

These significantly hotter summers present a challenge that we must adapt to. How will we protect ourselves from increases in excess heat deaths and increased fire danger, and our ecosystems from enhanced warming?

While we have already locked ourselves into a future where 2015 will rapidly become a new normal for the globe, we can still act now to reduce our vulnerability to future extreme events occurring in our region, both through cutting emissions and preparing for increased heat.

The Conversation

Sophie Lewis, Research fellow, Australian National University

This article was originally published on The Conversation. Read the original article.

This summer’s sea temperatures were the hottest on record for Australia: here’s why


Elaine Miles, Australian Bureau of Meteorology; Claire Spillman, Australian Bureau of Meteorology; David Jones, Australian Bureau of Meteorology, and David Walland, Australian Bureau of Meteorology

The summer of 2015-2016 was one of the hottest on record in Australia. But it has also been hot in the waters surrounding the nation: the hottest summer on record, in fact.

Difference in summer sea surface temperatures for the Australian region relative to the average period 1961-1990.
Australian Bureau of Meteorology

While summer on land has been dominated by significant warm spells, bushfires, and dryness, there is a bigger problem looming in the oceans around Australia.

This summer has outstripped long-term sea surface temperature records that extend back to the 1950s. We have seen warm surface temperatures all around Australia and across most of the Pacific and Indian oceans, with particularly warm temperatures in the southeast and northern Australian regions.

Last summer’s sea surface temperature rankings for Australia.
Australian Bureau of Meteorology

In recent months, this warming has been boosted – just like land temperatures – by natural and human-caused climate factors.

Why so warm?

These record-breaking ocean temperatures around Australia are somewhat surprising. El Niño events, such as the one we’re currently experiencing, typically result in cooler than normal Australian waters during the second half of the year. So what is the cause?

The most likely culprit is a combination of local ocean and weather events, with a substantial contributor being human-caused climate change.

In the north, the recent weak monsoon season played a role in warming surface waters. Reduced cloud cover means more sunshine is able to pass through the atmosphere and heat the surface of the ocean. Trade winds that normally stir up the water and disperse the heat deeper into the ocean have also remained weak, leaving the warm water sitting at the surface.

In the south, the East Australian Current has extended further south over the summer. This warm current flows north to south down Australia’s east coast. Normally it takes a left turn and heads towards New Zealand, but this year it extended down to Tasmania, bringing warm waters to the south east.

This current is also getting stronger, transporting larger volumes of water southward over time. This is due to the southward movement of high pressure systems towards the pole.

High pressure systems are often associated with clear weather in Australia, and when they move south they prevent rain. This southward movement over time has also been linked to climate changes in our region, meaning that changes in both rainfall and ocean temperatures are responses to the same global factors.

We’ve also seen high ocean temperatures in the Indian Ocean. Around 2010, temperatures in the region suddenly jumped, likely because of the La Niña event in the Pacific Ocean. The strong events during this period transferred massive amounts of warmth from the Pacific Ocean into the Indian Ocean through the Indonesian region.

The warmer waters in the Indian Ocean have persisted since and have influenced land temperatures. The five years since the 2010 La Niña are the five hottest on record in southwest Western Australia (ranked 2011, 2015, 2014, 2013 and 2012).

What are the impacts?

The world’s oceans play a major role in global climate by absorbing surplus heat and energy. Oceans have absorbed 93% of the extra heat trapped by the Earth since 1970 as the greenhouse effect has increased. This has lowered the rate at which the atmosphere is warming – which is a good thing.

However, it also means the oceans are heating up, raising sea levels as well as leading to more indirect impacts, such as shifting rainfall patterns.

As a nation that likes to live by the coast as well as enjoy recreation activities and harvest produce from the sea, warmer-than-usual oceans can have significant impacts.

Australia derives a lot of its income from its oceans and while such impacts aren’t often seen immediately, they become apparent over time.

Warm sea temperatures this summer and in the past have seen declines in coral reef health, and strains on commercial fisheries and aquaculture. The Great Barrier Reef is currently experiencing coral bleaching amid very warm water temperatures.

Our neighbouring Pacific islands have also seen the impacts of these very high sea surface temperatures, with recent mass fish kills and coral bleaching episodes in Fiji.

The impacts of warmer ocean temperatures are also felt on land, as ocean temperatures drive climate and weather. Abnormally high sea surface temperatures may have contributed to the intensity of Cyclone Winston as cyclone potential intensity increases with ocean temperature.

What is the outlook?

The seasonal outlook from the Bureau of Meteorology shows El Niño weakening over the next few months. This typically means cooler weather and can mean more rain on land.

However, closer inspection shows surface temperatures over the entire Indian Ocean and coastal Australian waters will very likely continue to remain well above average for the next few months. There are currently signs that surface currents are moving warm El Niño waters from the eastern Pacific over to the western Pacific, towards Australia.

There is potential for the East Australian Current to continue to transport this warmth to southern waters as far as Tasmania. Warm water could also be transported through Indonesia and travel south along the Western Australian coast via the warm Leeuwin Current, potentially causing further warming of already record warm waters.

So for the near future, the waters are going to continue to be warm. That’s good news if you’re heading to the beach, but not so good for the environment.

The Conversation

Elaine Miles, Ocean Climatologist , Australian Bureau of Meteorology; Claire Spillman, Research Scientist, Australian Bureau of Meteorology; David Jones, Scientist, Australian Bureau of Meteorology, and David Walland, , Australian Bureau of Meteorology

This article was originally published on The Conversation. Read the original article.