A supercharged “Summer is Coming”
New Zealand Climate Crisis: No 13
A SUPERCHARGED “SUMMER IS COMING”
[3700 words - a 15 minute read]
INTRODUCTION
In George R.R. Martin's book series, A Song of Ice and Fire and the HBO television adaptation Game of Thrones, the motto of one of the key protagonist families (the House of Stark) was that “Winter is Coming”. The phrase was a metaphor for both the importance of staying prepared to meet a specific impending seasonal challenge - winter in this instance and what it brings with it - and also the challenges that life presents
Here in the South Pacific, and in the real world, we face a different but still formidable challenge; that of increasingly hot summers (and other seasons) that are the signature physical manifestation of the climate change process we have set running, including, in this coming year, the complication of a supercharged El Nino[1] adding to the mix.
At one level it is deeply ironic that the impacts of the signature process of climate change on our health is an issue that we are least prepared to deal with. More importantly, the impacts of this excess heat will, directly and indirectly, adversely affect our communities and, again like other aspects of climate change, the impacts will hugely disproportionately (and in this instance also literally) affect the health and even the lives of our community members who are least resourced and least able to protect themselves from this threat.
The issue of heat - like many in the climate change fold - is one that badly needs attention paid to it, by families, businesses, communities and, especially, by our elected leaders in local and central government.
As a nation, we are rightly, albeit belatedly, becoming increasingly sensitised to the myriad ways that our love affair with burning fossil fuels and the ongoing global warming that has resulted - the outcome of the climate change process that we have set running - and which is threatening our communities.
Despite this, the current coalition government has been wilfully blind to the increasingly urgent challenges that climate changes poses and, appallingly, remains focused on dismantling the systems that have been put in place to address the issue.
As it stands, our emergent sensitivity to climate matters is primarily focused on the immediate, damaging impacts of severe weather events (such as flooding and landslips) that current climate crisis is delivering to us and will be doing so both more frequently and with increasing severity in coming years.
The reason for this belated, burgeoning interest in climate change is not hard to find; it is a case of “follow the money” . A large proportion of many New Zealander’s wealth is tied up their house/s and other property so any suggestion that this could potentially be put at risk by climate change exacerbated weather events will certainly focus their minds (and their votes) on this issue - and, more specifically on how this potential loss might be averted.
How New Zealand adapts to climate change and its impacts is a vital issue, and there is no more important subject than how our some of our at-risk communities will physically need to adapt (options here include manage retreat whereby buildings and/or infrastructure are physically relocated or rebuilt in a less hazardous place) but, functionally, and in the absence of any government leadership, the discussion is currently being led by the insurance sector.
As commercial entities, they are profit driven and accountable to their shareholders. The increasing frequency and cost to the sector, of climate change exacerbated severe weather events , together with better risk modelling tools, have accelerated a move to property level, risk-based pricing model that helps identify the specific hazards that a property is exposed to and so whether or not it can be insured against these - and what the costs of doing this are.
While successive New Zealand governments have been willing to spend large sums of money to help communities recovering from adverse events the same cannot be said for their willingness to invest in advancing resilience. The matter has not been helped by the extreme reluctance of the government to provide any leadership on this matter. The issue of cost shares - what entities (e.g. central government, local government, property owners) will pay and the proportions when properties have to be relocated - has been deferred to at least the next Parliamentary term. It is one that successive governments have managed to avoid being linked to as the political cost share calculus is unfavourable no matter the outcome - unless all the costs involved will be met by the government, something which is not likely to be doable.
Having a focus on adapting our buildings and infrastructure to make them more resilient to severe weather impacts is, of course necessary but of itself is not sufficient to help communities withstand the other challenges that climate change will pose.
WHERE DOES THIS LEAVE THE VITAL ISSUE OF US UNDERSTANDING AND ADAPTING TO THE GROWING HEALTH IMPACTS OF CLIMATE CHANGE?
Unaddressed is the answer, for a number of reasons.
Firstly, because human societies have developed very rapidly over a very short period of time. In terms of the ability of the human race to deal with the elevated temperatures that are the signature of the climate crisis that we now face, the process is complicated by legacy issues around risk management and hard limits around the temperature at which the human body can survive
Over the past 11,000 years (the Holocene period[2]) humans, and the other species we share the planet with, have benefitted from a very stable and resource rich physical environment. All human civilizations and the emergence of modern society as we know it today have happened during this time.
While the Holocene is significant in terms of human lifetimes - being between 330 and 500 generations - it is the equivalent to the blink of an eye in evolutionary terms; humans began to diverge from apes ~6 million years ago and there has been life on Earth for some 3.8 - 4 billion years of its 4.5 billion year existence.
As important as these recent changes to our societal structure and functioning are, evolutionary pressures over much longer time periods (or, functionally, the emergence and consolidation of physical and mental traits, in response to changes in our environment that have kept our ancestors and us - to date - from becoming extinct) have also played a critical role. These pressures and the responses of species to them been occurring for millions of years and will continue as long as life on Earth exists.
What is important in the current context are:
1. Changes in the way human lifestyles have developed over the past 10,000 years have outpaced the ability of our brain to keep up in evolutionary terms. One example of this - called temporal or delay discounting - is that the brain tends to strongly devalue future risks/rewards (e.g. that of climate change impacts, value of decarbonisation) are compared to immediate ones (e.g. the risk of being eaten by a sabre-toothed tiger or its 21st century equivalent - the convenience of driving ICE vehicles)
2. Life on Earth has evolved under relatively stable and temperate conditions. The last time that the planet experienced a 1.5 - 2°C temperature increase was in the mid-Pliocene warm period around 3 million years ago - well before the emergence of anything that resembled modern human society.
3. Lastly, while human beings have (through the use of clothing, tools and shelters) the ability to adapt to limited climate extremes - such as arctic and tropical temperatures - the physiological mechanisms that control homeostasis, including thermoregulation, were developed some 500 million years ago. These set hard limits around what the human body can tolerate in terms of temperature
Secondly, geographical features have, to date, insulated New Zealand from the extreme heat seen elsewhere. Consequently, the lived exposure to the extreme and dangerous heat events that are occurring elsewhere in the world have been minimal here and so the profile of this risk remains low.
We have, to date, been spared the heat driven, forest fires that have devastated large areas of Europe in particular this year. Locally, a 2020 fire in Lake Ohau was considered significant and burned ~5,000 Ha. In contrast, continental land mass fires are orders of magnitude larger; the March 2026 Morrill fire in Nebraska covered >250,000 Ha, the “Black Summer” bushfires of 209/20 in Australia covered 17 - 24 million ha and the 2026 fires in Europe have so far burnt >500,000 ha.
Accidents of geography (such as New Zealand having a small narrow land mass surrounded by oceans) have enable us to escape the out-of-control wildfires with direct, health and other impacts currently facing Europe, but we cannot be complacent about the threats posed to our health from climate change as we remain woefully under-prepared to deal with this issue.
Thirdly, because ambient temperatures in New Zealand (and in some other parts of the world) have broadly been within the limits that we are used to experiencing, and because the full impacts of climate change - and the increased ambient temperatures that have been generated as a result - are still to be felt, there is very little public awareness relating to heat related morbidity and mortality risks and how rapidly the serious health impacts they are associated with can develop
In part, this is due to the fact that people’s perception of heating as something they experience is very heavily weighted towards short-term temperatures (i.e. days/weeks). This is the level of data that many people focus on but comparing global average temperature increases against localised daily/seasonal temperature variations is misleading. The reason is because the latter data set includes significant but very localised variations that do not require large amounts of heat in relative terms, but increasing the former (i.e. the global average temperature) requires increasing the temperature of all the Earth’s surfaces; the land, atmosphere, ice and oceans. Achieving the latter requires a huge amount of energy[3].
In short, the rate of temperature increase that climate change is predicted to deliver appears small relative to the daily temperature variations that we already experience but this comparison is misleading.
In addition, (and perhaps owing to the fact that humans and our early ancestors have enjoyed the status of being the Earth’s apex predator for some 2 million years),and have modified our environment with apparent impunity for more than 5,000 years, there is little general recognition that, while we are very adaptable, we are not very physically robust; our bodies are ~60% water by weight only a semi-permeable, thin (~2mm thick) skin encloses many of our vital organs
While human beings, with suitable equipment/shelter, can survive temperatures from <-50°C to >+50°C, the vast majority of the human race has learned to comfortably live within a relatively narrow band of environmental and climatic fluctuations (~6°C to ~28°C). Just as importantly, the crops, livestock and irrigation that produce the world’s food were developed, discovered and designed within these temperature constraints.
The human body operates a complex thermoregulatory system designed to maintain our body’s core temperature at ~37°C for the optimum performance of the complex organic cellular processes (such as enzymes) that keep us alive. These processes are also responsible for setting the upper and lower temperature bounds at which we can survive; above 43°C the enzymes denature and stop functioning and below 21°C, cellular processes slow to the point that they can’t keep us alive
While the air temperature is important, the impacts from heat depend on a combination of temperature and humidity. Humidity is critical because we sweat to cool down and it is the evaporation of the sweat from the skin that actually removes heat from our body. In very humid conditions the air is already saturated with moisture and so cannot easily absorb sweat which therefore stays on the skin and therefore doesn’t provide any cooling effect.
Combining temperature and relative humidity - the latter is the measurement of the amount of water vapour (in percent) in the air compared to the maximum amount of water the air can hold at a specific temperature - can be combined to provide a readily calculated heat index figure, as a measure of how hot it feels
When the temperature/humidity combination is such that we cannot cool down by sweating, this prevents the body’s thermoregulatory system’s ability to maintain our core body temperature and we begin to overheat, with catastrophic results if untreated or we are not removed from the heat source
What is not yet widely recognised is just how low this temperature/humidity level can be before major health problems occur. Recent work has suggested that, at an 80% humidity level – the average humidity in Auckland – the likelihood of a heat disorder arising from prolonged or strenuous activity is considered to be “dangerous” at a 31°C wet bulb temperature[4] and “extremely dangerous” at 36°C. Under certain conditions - a high temperature and low humidity - the safe limit may even be as low as ~26°C for healthy young people and ~22°C for older people, albeit this is a condition that is rarely reached currently here as New Zealand's temperate, maritime climate keeps typical summer wet-bulb levels safely in the mid-to-high teens or lower.
THE HEALTH IMPACTS OF ELEVATED TEMPERATURES
It is important to recognise that not all heat impacts are bad for us and that some temperature changes are beneficial. For example, a decrease in the number of very cold days means fewer cold-related deaths and hospitalisations from some cardiorespiratory (heart and lung) conditions such as pneumonia.
However, any benefits are likely to be outweighed by a projected increase in heat-related death and illness, with Northland, the east coast of the North Island, and parts of the Bay of Plenty are likely to be the regions where people will be particularly affected.
Human beings have evolved to survive and operate within a relatively narrow temperature range and so are not well equipped to handle to the higher temperatures that climate change will bring and need to act to safely manage elevated ambient temperatures and that high nighttime temperatures have particularly significant impacts on our health.
Vulnerability to climate change is dependent on people’s exposure to the impacts, their sensitivity to the effects and their level of resilience and ability to adapt to the changes to which they are exposed. Key vulnerable population groups here include:
§ Children aged 0-4 years
§ Older adults aged 85+ years
§ Māori
§ People living in poverty (living in lower deciles of the New Zealand Index of Deprivation
§ People working in primary industries.
THE HIGHLY VARIABLE MAGNITUDE OF THE GLOBAL IMPACTS OF CLIMATE CHANGE HEATING
As noted above, New Zealand has been much less affected by global warming generated heat than many other developed countries including Europe. As bad as the situation is that Europe is facing, it is important to remember that the heat related impacts are not spread evenly around the world and that the situation is much worse in other countries. A recent Climate Impact Lab (CIL) report [5] suggest that, by 2050, 390,000 people in the Global South[6] will die from the effects of extreme heat - ten times more than the 39,000 deaths expected in the Global North[7].
An even more recent CIL report[8] found that the regions most affected by extreme heat are also the regions least likely to have increased levels of electricity to power the air conditioning that might provide relief. Use of cooling-related electricity is projected to grow seven times more in middle-income countries than in low-income countries in response to climate change.
Looking further out, the picture is even bleaker for some parts of the world and the Global South in particular. If the world, as seems likely, is approaching a 3°C temperature rise by 2090, then ~2.7 billion people will be living in parts of the world that are uninhabitable.[9],[10]
Short of death, there is no more severe impact from climate change than having the place you inhabit no longer being able to sustain your life or that of the community, but this what the future holds for many people as a consequence of climate change induced global heating. The coming tsunami of climate change refugees is a situation that the parts of the world that remain survivable need to urgently prepare for.
WHAT CAN BE DONE TO MITIGATE THE HEAT IMPACTS OF CLIMATE CHANGE?
Buildings in developed countries that have much higher ambient temperatures than New Zealand have, traditionally, included passive design features, in their builds that have enabled their inhabitants to live comfortably in environments where peak daytime temperatures have traditionally reached 35°C - 40°C.
However very few New Zealand homes and other buildings are designed with such heat management features in mind. In addition, despite design elements including passive cooling features, such measures are increasingly being shown to be inadequate in the face of the current heatwaves in Europe where peak daytime temperatures are reaching past 40°C. In addition, high nighttime temperatures (over 25°C) and urban heat island effects prevent buildings from releasing stored energy at night, inhibiting people’s ability to recover from the increasingly hot days.
What are the lessons for New Zealand as we prepare to deal with increasing future heat impacts here?:
1. Passive design features are not necessarily enough to manage the level of temperature increase that climate change will deliver (and will continue to deliver until such a time as our GHG emissions are substantially reduced).
2. Where passive design is not sufficient, then mechanical, electrically powered space cooling devices - and especially air conditioning- are needed. This mitigation measure inevitably raises a number of difficult issues, the most important one being equity, not least because the installation (capital cost) and utilisation (operating cost) of air-conditioners cost money and not everyone has the money for this. The consequential impacts of any shortfall will most significantly affect the groups least well placed to absorb the impacts of heat; the poor, the ill and the elderly.
3. New Zealand buildings have historically, been oriented around cold climate design and so the focus has been on space heating (i.e. warming the building up in cold weather) rather than passive space cooling.
4. It has been suggested that policymakers should treat space cooling as a public health tool, rather than a discretionary good, and that this premise should be used to support these communities having access to space cooling.
5. The planning and development of urban design features will become increasingly important as towns and, especially, cities, have to deal with increasing levels of heat over the coming years and decades. Measures may include the provision of community refuges: This would involve ensuring public buildings (such as libraries) have air-conditioning that have adequate capacity to manage an influx of people who can use the facilities to cool off when necessary and provide awnings or other structures to provide shade in high traffic pedestrian zones and transit stops.
Managing the effects of the coming climate change driven heat impacts on our health requires us to make major changes to (1) the way we live our lives and (2) the way our communities are designed and function.
Firstly, our housing stock and other buildings need to pivot from a focus on space heating (i.e. how do we keep our house and other building warm enough in cold weather) to space cooling (i.e. keeping buildings cool enough in hot weather). This can be effected through the incorporation of passive design features in buildings and/or by utilising space cooling technologies such as air conditioners and heat pumps. Passive design is capable of providing the necessary cooling initially but has been shown to have limited capacity in the extreme heat situations that Europe is currently facing. Retrofitting these features to buildings will also be expensive. Air conditioning and heat pumps are highly effective, but widespread adoption will require that equity issues around purchase and operation be resolved and their expanding use will see an increasing demand on the national power grid.
Secondly, (and unless everyone has access to adequate and effective space cooling technology) purposeful urban design - operating at a town/city level - has a significant role to play as a safety net to help protect those people who are less - or otherwise un-protected from the heat. This stratagem can be utilised at a range of levels and circumstances and should be part of the toolbox used by local authorities whenever they collaborate with their communities to adapt to climate change impacts.
In summary, we know about the many challenges - including an increasingly hotter environment - that current climate change process will pose to our communities and businesses and society. Regrettably, we remain woefully underprepared for what will happen and we appear unwilling to make the changes to our way of life that addressing the matter requires.
Be assured however that, to paraphrase GRR Martin, “Summer is coming” whether we are ready or not.
[1] Lineham L, NZ Herald, “The risks and what is being done to prepare for a strong El Niño this summer” 13th August 2026.
[2] The Holocene Epoch is the current geological time period. It is part of the Cenozoic Era [sixty-six million years ago to present] and the Quaternary Period [2.6 million years ago to present] It started about 11,700 years ago after the last major ice age ended.
[3] It is estimated to require ~3 x 10 22 Joules to produce a 0.1C global temperature increase. For comparison, this is equivalent to detonating 15x “Hiroshima” sized(1945) atomic bombs (6.3 x 10 13 Joules) every second for a year. [Another fun fact; at our current emissions rate, it takes Earth roughly 2.5 to 3 years to accumulate 0.1C of warming]
[4] Where a wet, wicking material is wrapped around the bulb of the thermometer to enable humidity to be taken into account
[5] Grover-Kopec E et al, Climate Impact Lab, ”ADAPTATION ROADMAP Human Health Measuring the impact of rising temperatures on mortality to target adaptation planning”, March 25, 2026. https://impactlab.org/research/human-health-measuring-the-impact-of- rising-temperatures-on-mortality-to-target-adaptation-planning/
[6] "Global South" is a broad political and socioeconomic term rather than a strict geographical boundary and includes nearly all African Nations; Central and South America, and Caribbean island states; most of Asia excluding Japan and South Korea) and developing Oceania island nations and territories (excluding Australia and New Zealand)
[7]The “Global North” includes USA and Canada; the EU and UK; Japan, South Korea, Australia, and New Zealand together with Israel.
[8] Grover-Kopec E et al, Climate Impact Lab, “ADAPTATION ROADMAP Energy Measuring the impact of rising temperatures on energy consumption to target adaptation planning” July 27, 2026. https://impactlab.org/research/energy-measuring-the-impact-of-rising-temperatures-on-energy-consumption-to-target-adaptation-planning
[9] The areas include Central America, much of northern South America, much of northern Africa, most of the Arabian Peninsula, almost all of Southeast Asia, a big part of Northern Australia and most of India, Pakistan and Bangladesh.
[10] Earle S “Runaway Climate. What the Geological Past Can Tell Us About The coming Climate Change Catastrophe” New Society Publishers, 2024, pp 125 -9
