We Can’t Air-Condition Our Way Out of a Hotter Future

We Can’t Air-Condition Our Way Out of a Hotter Future

Beige concrete building with air conditioning units under a clear blue sky, showcasing minimalist urban architecture. by Abdelrhman Magdy via Pexels

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We can’t air-condition our way out of a hotter future, says UNSW expert

UNSW Newsroom – 2 July 2026
Samantha Dunn
Samantha Dunn

A new global review argues passive cooling technology must become central to climate adaptation.

As temperatures rise around the world, air conditioning is saving lives. But a growing reliance on it is also placing unprecedented pressure on electricity grids, increasing greenhouse gas emissions and making cities even hotter.

A global review led by UNSW Sydney’s Professor Mat Santamouris AM – an expert in innovative heat mitigation technologies and strategies for cities, opens in a new window – argues that keeping buildings cool without relying solely on air conditioning will be critical for adapting to climate change.

Published in Nature Reviews Clean Technology, opens in a new window, the review examines the latest advances in passive cooling technologies, from emerging materials for radiative, evaporative and combined radiative/evaporative cooling to sophisticated solar control systems and personalised intelligent ventilation technologies that can help buildings shed heat without consuming electricity.

Prof. Santamouris says passive cooling should no longer be viewed as a niche architectural feature, but as essential infrastructure for a warming world, opens in a new window.

“Air conditioning saves lives and will remain essential during extreme heat,” he says. “But we cannot air-condition our way out of climate change. If every building depends entirely on mechanical cooling, we create enormous pressure on electricity systems while adding even more heat to our cities.”

 Summer street scene in Firenze, Italy, during a heatwave. People walking under the strong Tuscan sunlight with refreshing water mist in the urban atmosphere.

As European cities experience some of their hottest recorded temperatures over recent weeks the question about how to keep populations cool is front of mind.Photo: Richard Vanlerberghe / Unsplash

Demand for cooling is soaring

The review highlights the rapid growth in cooling demand worldwide, opens in a new window. Global electricity consumption for cooling has reached almost 10 per cent of total electricity use, opens in a new window, with around 10 new air conditioners sold every second, opens in a new window. By 2050, the number of residential air-conditioning units is projected to increase to almost 5.6 billion worldwide, opens in a new window.

At the same time, billions of people living in hot climates still lack access to affordable cooling, opens in a new window.

Cooling buildings without relying on air conditioning

Passive cooling technologies, opens in a new window offer a way to reduce energy demand while making buildings safer and more comfortable, particularly for vulnerable communities.

“The best cooling strategy is to stop unwanted heat entering buildings in the first place. Shading, reflective materials, opens in a new window, smarter ventilation, opens in a new window and new cooling materials can dramatically reduce indoor temperatures before an air conditioner even needs to switch on,” says Prof. Santamouris.

Rather than replacing air conditioning, Prof. Santamouris and coauthor Dr Konstantina Vasilakopoulou from RMIT argue passive cooling should become the first layer of defence, with mechanical systems providing additional cooling only when required.

The review evaluates emerging innovative technologies, such as super-cool materials, combined radiative/evaporative coatings, sophisticated external shading systems and personalised ventilation, as well as known passive cooling technologies such as reflective cooling materials that release heat directly into the atmosphere and hybrid cooling systems that combine multiple passive approaches.

Integrating passive cooling strategies with efficient building design could reduce cooling demand by as much as 80 per cent, opens in a new window in hot climates while lowering peak electricity demand and improving resilience during power outages, according to the review.

 

The buildings we construct today will still be standing in 2050 and beyond. They need to be designed for the climate they will experience, not the climate we had in the past.
Professor Mat Santamouris AM

Cooler cities, healthier communities

Beyond reducing energy use, the researchers say passive cooling can make cities healthier and more resilient as extreme heat events become more frequent.

Keeping buildings and neighbourhoods cooler can reduce the risk of heat-related illness, ease pressure on electricity networks during heatwaves and improve comfort for people who cannot afford to run air conditioners. Passive cooling measures can also help buildings remain safer during power outages, when mechanical cooling systems are unavailable.

Prof. Santamouris says the greatest benefits will come from combining passive cooling with efficient air conditioning, rather than treating them as competing approaches.

“There is no single solution to keeping cities cool. We need a whole-system approach that starts with climate-responsive building design, shading and better materials, then uses the most efficient cooling technologies only when they are really needed.”

The review calls for stronger building standards and planning policies that encourage climate-responsive design, alongside investment in technologies that reduce heat entering buildings and lessen demand on electricity infrastructure as cities continue to warm.

Designing buildings for tomorrow’s climate

Buildings designed today will need to withstand a much hotter climate over coming decades, says Prof. Santamouris.

“The buildings we construct today will still be standing in 2050 and beyond. They need to be designed for the climate they will experience, not the climate we had in the past.”

In order to achieve this governments should strengthen building standards, support passive cooling technologies and improve access to affordable cooling for lower-income communities.

Prof. Santamouris says these measures could deliver significant benefits for public health, energy security and climate resilience.

“Cooling should not be a luxury available only to those who can afford rising electricity bills. Better building design can reduce costs, improve comfort and help protect the people most vulnerable to extreme heat,” he says.

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The Role of the State in Fostering Growth and Innovation

The Role of the State in Fostering Growth and Innovation

Scenic view of Muscat’s traditional architecture against rugged mountains during the day. by Uğurcan Özmen via Pexels

What is the role of the state in fostering growth and the green transition?

Action to address climate change can drive strong, sustainable growth. The state is central in setting the direction of change and mobilising investment and innovation to achieve it. But time is not on our side. Research to guide policy has never been more urgent; it must proceed alongside action.

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This article is part of an upcoming collection on state capacity and industrial strategy by the Policy Hub for the Huth Initiative for a New Political Economy.

The new growth story of the 21st century must be about sustainability and resilience, and with artificial intelligence (AI) at centre stage. It will be very different to the polluting and unsustainable models that so many countries have followed. Private investment will be at the core. But the role of the state will be critical in making it happen. The task of governments and public institutions is to devise comprehensive strategies, policies and institutions that can foster transformation across all economic sectors.

The role of the state must include setting incentives, aligning expectations and spurring innovation and entrepreneurship. It will be in the vanguard of system change, including in our cities, energy, transport, land and water.

This requires a clear strategic vision, tackling market failures and encouraging private investment in new areas. At the same time, it must manage the socio-economic and political challenges arising from dislocation and vested interests. And it must be aware of and avoid the dangers of government failure. In so doing, it must beware both market and institutional fundamentalisms.

These are ambitious tasks that require a renewed and effective state. This article outlines key dimensions of the state action that are needed to enable this growth story. Together, they form both a sense of direction and a research agenda. Because of the urgency, action and learning must go together. There will be mistakes along the way, but this should not be an argument for inaction. Delay is dangerous.

This is a time of crisis – and a new growth story is needed

Much of the global political landscape is currently divided. Across the world, there has been erosion of constitutional democracy. Some of this is related to the sluggish economic growth that the world has been experiencing, eroding living standards for many, undermining communities and leading to anger and discontent.

In this context, climate action has been characterised by many as an issue for elites. Yet it is not sustainability-aligned policy that has led the world to its current state. On the contrary, the lack of it has contributed to the difficulties. Climate inaction creates instability, migration and conflict. Climate action drives growth.

Transforming our economies towards sustainability can provide exactly what is needed to overcome the political and economic difficulties of the present: integrated, well-designed and well-implemented public policy and institutional structures that drive development through private and public investment, innovation and systemic change. Such actions can unleash the forces that will transform our economies, creating strong, sustainable, resilient and inclusive growth.

Climate action will drive the new world growth story. There is no inevitable trade-off between climate action and growth: the former drives the latter. And it is a much more attractive form of growth than the dirty and destructive models of the past.

Developing nations, where most of future growth and investment are set to happen, are at centre stage. In these places, most of the infrastructure remains to be built, the vast majority of the world’s renewable resources are concentrated and the investment needs are the greatest. Their cities can be built in different ways, choosing health and efficiency over pollution and congestion; their agricultural systems can combine local knowledge and AI to become smarter and less toxic; and their economies can leverage their clean endowments, potentially benefiting from a new world economic geography where abundant clean energy or the availability of specific minerals is a key asset.

Strong investments and innovation are necessary across the whole economy – see Figure 1 for five key climate investment areas. Such investment must reach all forms of capital, including physical, natural, human and social.

Clean energy investment drives development; natural capital investment underpins it; adaptation and resilience investment sustains it; and just transition investment makes change equitable, desirable and possible. This investment would strengthen demand, supply and efficiency in the shorter term; stimulate innovation and discovery, creating new investment opportunities in the short and medium term; and avoid the destructive impacts of climate change in the longer term. Carbon-intensive growth self-destructs; it is not a viable option.

Alongside the necessary increase in investment, the growth story comes from a number of key drivers (see Figure 1):

  • Lower costs and technological advancement, with the clean already being cheaper than the dirty across much of the economy, and innovation proceeding apace across most action areas.
  • Increasing returns to scale, shown by many new products and activities.
  • Increased resource efficiency, leading to higher productivity.
  • Reduced pollution, improving health, reducing mortality and increasing productivity.
  • Improvements in the key systems of cities, energy, transport, land and water – for example, cities where you can move and breathe are much more productive than those that are heavily polluted and congested.

AI can magnify these drivers, enabling green and intelligent growth (Stern et al, 2025). See The Growth Story of the 21st Century (Stern, 2025) for a further description of the drivers of growth.

Figure 1: Key investment sectors and growth drivers

The role of the state: five key areas for action

The role of the state as indicated above is crucial to the delivery of the growth story. It will chart a path, and thereby expectations, create the conditions for investments, steer action towards shared objectives and help to bring society together. The remainder of this article focuses on five key areas for state action. These are also priority areas for research, which must move quickly and alongside action. Time is not on our side.

National strategy and direction

Structural change at speed requires strong political support. The state must establish a clear direction and craft a compelling national vision and narrative. And it must act so that some of the tangible benefits of change are experienced directly and soon. It is crucial to foster a shared understanding that the transition is a growth story with sustainable and resilient investment at its core. This narrative both resists the separation of climate and development, and tackles misinformation.

There is no doubt that many challenges will arise, but the role of the state is to make practical choices to overcome them. The narrative should be one of hope, presenting climate policy for what it is: action with the objective of advancing development and wellbeing. It is about technological innovation, modernisation, efficiency, creation of job opportunities, industrial dynamism, resilience and more.

It is a narrative and strategy that highlight both the growth story that action enables and the immense curtailment of rights to and opportunities for development that inaction causes. By creating a hostile environment, climate change can erode fundamental human rights, such as access to food and health, and damage economic and human development across the board. The argument should also embrace a discussion of what is ethical and responsible in relation to future generations and others in the current generation (Stern, 2026).

Such narratives and action plans were embodied in the European Union’s Green Deal and the US Inflation Reduction Act.

Comprehensive management of market failures

A core task in generating change and building support is the tackling of key market failures (Stern, 2022), thus reframing incentives and helping to create the conditions for the required investment flows. These market failures, which are many and interwoven, must be tackled together in complementary ways.

A narrow understanding of market failures, highlighting only the externality from greenhouse gas emissions, has led many economists to focus overwhelmingly or exclusively on pricing carbon emissions in formulating policy. Such pricing is indeed a critical part of policy, but it must be complemented by action on other key important failures.

These include research and development (R&D) and innovation, which stem from creators’ inability to capture the full value of their ideas due to knowledge spillovers. Without policy, that leads to under-investment in innovation. Research shows that combining carbon pricing and R&D can be much more powerful than carbon pricing in isolation (Acemoglu et al, 2012).

Another critical market failure concerns networks. Without policy, markets do not adequately account for network interdependencies and can ignore systemic risks and opportunities. Understanding and acting to improve ‘feedbacks among interacting elements’ (Catanzaro and Buchanan, 2013) can bolster efficiency and unlock economic value. For example, the quality of urban mobility is linked to urban planning decisions, the value of having an electric car to the availability of chargers, the viability of clean energy generation projects to grid availability, and so on.

Further important market failures concern information – for example, on how products have been made and other co-benefits where health from avoided pollution can be of great importance (see Figure 2). Capital market imperfections can hinder finance for the strong new investments that are required – development banks can play a key role here.

Figure 2: Key market failures related to climate and sustainable development

Institutional strength, governance and the investment environment

Policy predictability, coherence and a clear direction of change are all fundamental in building the confidence needed to foster investment in the green transition. Policies will change as circumstances change and learning takes place.

But for investor confidence, such change should be ‘predictably flexible’. Criteria for flexibility should be transparent – for example, reducing subsidies for renewables as and when costs fall and diffusion occurs. Concerted action across government, to foster policy alignment, and convening stakeholders, to generate cohesive action, can advance investment more quickly than measures that are uncoordinated across ministries.

‘Country platforms’ can provide mechanisms for coordinating the mobilisation of domestic and international sustainable finance in alignment with national development priorities. Standards and regulation can guide investments and signal which forms are consistent with the long-term trajectory of the economy, in alignment with sustainability goals. As far as possible, sharing standards and coordinating strategies across countries can enlarge markets and accelerate progress (Bhattacharya et al, 2025).

An example of consistency in policy-making is in Uruguay. The country has attracted clean investment and transformed its electricity matrix in less than two decades through sustained and clear policy and regulation. It has also built credibility in innovative ways: by holding itself accountable for climate action, having established a sovereign bond with a structure where, if its aims are not met, it will pay a higher interest rate (Godfrid et al, 2025).

Further, creating a positive investment environment requires strong macroeconomic policies, which are fundamental to ensuring the high investment levels needed in sustainable sectors are translated into increased output and not just a crowding out of private investment. Debt management is part of that story. Legal institutions are also of great importance in offering clarity on obligations and for dispute resolution.

Industrial policy for a dynamic and green private sector

Fostering private investment in the new growth story requires tackling market failures, building credibility in strategy and policy, and creating a strong investment environment across the whole economy. It also involves identifying where a country’s clean economic potential and comparative advantage lie. Such was the case with the Danish government’s support for private firms and entrepreneurs in the wind power sector, which was key to creating the country’s renowned innovation ecosystem (Technology Executive Committee, TEC, 2023).

Providing the right support requires that each country crafts tailored measures, as Japan did through its Ministry of International Trade and Industry, which selected and ‘nurtured’ industries through customised measures such as tax breaks and low-interest loans, accelerating their development (Johnson, 1982). Industrial clusters can drive sectoral growth by enabling economies of scale and collaboration, as seen in China (World Economic Forum, WEF, 2026).

Fortunately, the misguided sneering at ‘industrial policy’ typical of the years of market fundamentalism of the 1980s and 1990s has subsided. Building new industries and transforming technologies in a purposive way requires strategy and policies.

While the majority of investment for the transition will be private, there will also be a critical role for public investment, a crucial element of the role of the state. For example, public transport will play a fundamental role. In many countries, the electricity grid will be owned by the public sector. In many cases, this infrastructure facilitates private activity and builds for long-term growth and prosperity.

Finance will play a key role in fostering a green private sector. Priorities include reducing investment barriers, such as high costs of capital. This frequently involves better management and sharing of risk. Given that domestic capital markets in many emerging markets and developing countries are shallow, facilitating access to financial instruments, such as foreign exchange hedging, as Brazil’s finance ministry has done through its Eco Invest programme, can have catalytic effects.

Adequate access to finance is also of importance for households, whose transition requires their own investment. Often poorer households face a higher cost of capital. How households and organisations are supported and costs distributed is a key part of policy for the transition. The national and multilateral development banks can play a central role both in helping to create the conditions for investment and in managing risk and reducing the cost of capital.

Building stability in trade and collaborating across frontiers in innovation and clean energy generation can accelerate the drivers of the growth story, with positive spillovers across countries. State leaders should work through coalitions of the willing to foster market expansion, resource sharing, cohesive policy-making, access to finance and more, contributing both to resilient supply chains and fostering innovation.

Building trust and coordination across countries can generate predictability, while conflict and volatility can be dangerous. Multilateral action is also of importance in tackling the debt, fiscal and financial constraints confronted by emerging markets and developing nations (Stern, 2021).

Public discussion, social buy-in and workforce adaptation

When the transition plans are put into action, there will be deliberate structural change at speed and scale. Some vested interests will push back, in particular fossil-fuel sectors where high rents are at stake. Without pro-active state action, ordinary citizens will face challenges that will understandably create opposition, from dislocation to increases in the cost of living. Careful policy design must manage these risks while pursuing the economic and social gains from change, which will vary across countries with different systems and structures.

Public action will be necessary to help to overcome dislocation, particularly by investing in people and places to create new opportunities, or by providing low-cost capital to help households to manage change. Some vested interests will have to be confronted head-on. Public discussion and building a shared understanding or narrative are crucial to political and social ‘buy-in’. That discussion will often be focused on localised interactions.

It is critical that policy sustains social buy-in and, for this, that the benefits of the transition are shown early. Successful interventions require designing policy packages that account for and reconcile varied interests, articulating and managing negative impacts well in advance.

Still, not all challenges can be foreseen; there will be difficulties and learning that arise along the way. As emphasised, being flexible while maintaining predictability is a critical element of policy-making, both for investment and acceptance. Thus, political systems must remain open and receptive to public input and should be active in initiating civic dialogue.

What Jürgen Habermas called the public sphere – the space in which public opinion is formed – can take many forms, including citizens’ assemblies. Well-managed transitions, rather than generating backlash, should benefit communities and their workers, potentially increasing support for incumbent governments. For example, one study suggests that Spain’s coal phase-out process had some electoral success, with government, industrial and social discussion playing an important role (Bolet et al, 2024).

Research and action

The five areas of action described (see Figure 3) are also five areas for research. In its pace and scale, the necessary transformation is unprecedented in economic history, except in wartime.

The urgency means that this is ‘public policy as if time matters’ (Stern, 2018). It concerns structural and systemic change across the whole economy of a nation. And it will lead to a new economic geography where activity moves towards low-cost clean energy. It will require financing for investment to move much more strongly into emerging markets and developing economies, where the majority of future economic growth will occur.

These are great challenges for both action and research, and they require a new economics of structural transformation. But research and action must move together. Delay is dangerous.

Figure 3: The role of the state – an action agenda

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Italy and EU Strengthen Jordan’s Cultural Heritage

Italy and EU Strengthen Jordan’s Cultural Heritage

The ancient Arch of Hadrian stands tall in Jerash, a significant Roman archaeological site in Jordan. by Hisham Zayadneh via Pexels

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Italy and EU Strengthen Jordan’s Cultural Heritage Through Innovative Site Development

The Italian Embassy to Jordan, supported by the Italian Agency for Development Cooperation (AICS) Office in Amman, recently convened key stakeholders to advance a strategic initiative focused on the sustainable development and enhancement of Jordan’s outstanding archaeological heritage at Mukawer, the historic site of St. John the Baptist’s imprisonment, and Abila, one of the cities of the dodecapolis. Funded by the European Union and implemented by the AICS in collaboration with the Department of Antiquities (DoA) and the University of Perugia, the project is aligned with the Kingdom’s national tourism development objectives and looks ahead to the 2029 and 2030 commemorations associated with the sites linked to St. John the Baptist (Machaerus Fortress) and Jesus Christ (the Baptism Site).

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The initiative aims to further strengthen Jordan’s position as a destination for religious and cultural tourism, while promoting a shared spiritual heritage rooted in both Christian and Islamic traditions and fostering long-term, sustainable economic growth.

Based on a fruitful and longstanding cultural partnership with Jordan, Italy is fully committed to contributing to enhancing archaeological sites not only as historical landmarks, but as dynamic resources for strengthening local communities and creating sustainable employment opportunities.

The implementation phase of the project “Support to the socio-economic recovery and promotion of sustainable local development through the enhancement of cultural heritage sites” will start through two key site events that will bring together local authorities, academic partners, technical experts and local community. These two events, a site visit at Mukawer on Thursday, July 2nd, 2026, followed by a session at Abila on Sunday, July 5th, 2026, will set a major milestone for the project’s execution. During both days, key partners will present upcoming works, expected results, and the framework’s archaeological, architectural, and conservation plans, marking the first major step forward after extensive preparation.

Beyond physical infrastructure, the project places strong emphasis on the protection of the landscape and the enrichment of the visitor experience. This includes significant investments in securing access routes to the Mukawer fortress and in the preservation of historical caves along the path, which serve to highlight the tangible and intangible heritage of the area.

Capacity building remains a central pillar of the initiative as well. Specialized training programs for the staff of the Ministry of Tourism and Antiquities (MoTA) and the Department of Antiquities (DoA) are scheduled to begin on July 14, in partnership with Yarmouk University, focusing on integrated conservation and advanced archaeological research methodologies.

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More Than 90% of New Renewables Are Cheaper Today

More Than 90% of New Renewables Are Cheaper Today

A young child playing on a rocky terrain near solar panels in Greece under a clear sky. by H O M A D via Pexels

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IRENA: More than 90% of new renewables are already cheaper than any fossil fuel power plant

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By Energía Estratégica • July 3, 2026

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The agency warned that solar and wind energy are not only consolidating their cost advantage, but have also become a key factor in reducing exposure to gas volatility and strengthening energy security.

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IRENA: More Than 90% of New Renewables Are Cheaper Today

IRENA

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Renewable energies consolidated their leadership as the most competitive option for adding new electricity generation capacity by 2025. But, in addition to the economic factor, they are beginning to play an increasingly strategic role in a scenario marked by geopolitical conflicts, volatility in fuel markets, and greater demands for energy security.

This is according to the report “Renewable Energy Generation Costs in 2025” , published by the International Renewable Energy Agency (IRENA), which concludes that more than 90% of the large-scale renewable capacity added during the year was cheaper than the lowest-cost fossil alternative .

The organization argues that the competitive advantage of clean technologies is no longer limited to the cost of generation: it also represents protection against international uncertainty and fluctuations in oil and gas prices.

Wind and solar power extend their lead

The report’s data shows that solar photovoltaic energy maintained an average cost of US$44/MWh , while onshore wind reduced its costs by 4% , to US$33/MWh , consolidating itself as one of the most competitive technologies on the market.

In the case of offshore wind , costs also continued to fall and reached US$78/MWh , 3% less than the previous year.

The contrast with fossil technologies was even more marked.

IRENA points out that the global shortage of turbines has practically doubled the capital cost to build new combined cycle power plants in the United States, while in markets with high gas prices, such as Germany, Italy and Japan , generation costs exceeded US$100/MWh .

Added to this is the uncertainty stemming from the crisis in the Middle East, which continues to put pressure on international gas markets.

A shield against energy crises

Beyond the cost of producing electricity, the report focuses on another growing benefit of renewables: reducing dependence on imported fuels.

According to IRENA, the currently installed renewable capacity made it possible to avoid purchases of fossil fuels of around US$480 billion during 2025 , reducing the exposure of numerous countries to the volatility of international markets.

“Every additional megawatt of renewable energy strengthens economic protection against fuel price fluctuations and protects consumers, businesses and public finances,” said Francesco La Camera, Director-General of IRENA.

The organization believes that the expansion of renewable energy generation has become a strategic investment both to improve economic resilience and to strengthen the competitiveness of countries.

The impact of the crisis in the Middle East

The report also analyzes the effects of the closure of the Strait of Hormuz that occurred in early 2026, which triggered a sharp increase in international prices for gas and other energy commodities.

In that context, existing renewable energy generation helped to mitigate the economic impact of the crisis.

In Indonesia, Thailand, and the Philippines alone, renewable energy installations avoided approximately US$5.7 billion in coal and gas purchases during 2025.

If those same volumes had been acquired during the peak prices recorded between March and May 2026, the cost would have amounted to approximately US$6.5 billion .

China leads the world in savings

IRENA’s analysis of the top twenty economies shows that renewable energy avoided US$377 billion in fossil fuel purchases during 2025.

China topped the ranking by a wide margin with US$177 billion , equivalent to almost half of the total savings.

Behind them were the United States , with US$35 billion , Brazil , with US$32 billion , Germany and India , with US$18 billion each, and Japan , with US$15 billion .

Costs will continue to fall, albeit more slowly.

Since 2010, solar photovoltaic energy has reduced its costs by 89% , while onshore wind power has fallen by 71% , concentrated solar power by 72% , and offshore wind power by 63% .

However, IRENA warns that the pace of that reduction could slow down.

The reorganization of the manufacturing industry in China, the increase in the prices of raw materials and components, the fall in investments in new factories and a trade context marked by greater tariff tensions are beginning to put pressure on installation costs.

Even so, the agency’s projections indicate that renewable technologies will continue to reduce their costs until 2035 , although at a slower rate than that recorded during the last decade.

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Two Centuries on, Experts Unlock Secrets of Red Sea . . .

Two Centuries on, Experts Unlock Secrets of Red Sea . . .

Stunning drone shot of Hurghada’s coastline and desert panorama during sunset. by Mo Ismail via Pexels

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Two centuries on, experts unlock secrets of Red Sea and Gulf of Aden sailing chart

Published by Phys.org – 3July 2026

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Two centuries on, experts unlock secrets of Red Sea and Gulf of Aden sailing chart

The document has been part of the Royal Geographical Society’s collection for 189 years. Credit: Royal Geographical Society


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Experts have unlocked secrets hidden for two hundred years in a beautiful navigational chart made for 18th century seafarers negotiating the Red Sea and Gulf of Aden. The paper scroll is evidence seafaring communities in the region used their own effective system of navigation that enabled trade and exchange between India, Arabia and the Horn of Africa in the age of sail, before the uptake of a more abstract, instrument-based navigation.

The Indian Kachchhi/Gujarati document has been part of the Royal Geographical Society’s collection for 189 years and is one of the most detailed surviving indigenous navigational charts produced in the Indian Ocean tradition.

New research shows it was an effective aide memoire, capturing and reflecting the intimate knowledge of sailors from modern Gujarat in India. It is a window onto the indigenous navigational practices of people across the western Indian Ocean.

Researchers have been able to identify and interpret place-names and astronomical data inscribed on the chart for the first time, establishing latitude and providing sailing directions and showing intimate local knowledge: the chart was not simply designed to facilitate long-distance transit to first-order Red Sea ports.

The chart, which is adorned with beautiful images of ships and religious buildings, dates from the late 18th or early 19th centuries. It was acquired by Alexander Burnes in 1835 from an un-named sea captain in Kachch. He donated it to the Royal Geographical Society. However, he and subsequent scholars were not able to translate and analyze the map to the extent that the current study has.

Where earlier readings fell short

The 66 or so Devanagari place names on the chart have never been fully transcribed and identified and most European scholars who appraised the chart wrongly claimed that it had no latitude or longitude information. They also thought the fact it did not show the real angle of the Red Sea and Gulf of Aden was a shortcoming, when in fact, it makes the chart more portable.

Experts have produced a projection of the chart that presents the information it contains spatially in a way familiar to modern maps. The cartographer who made the document depicts more than 180 islands, plus reefs and other features such as landmarks, religious buildings and flags.

Alexander Burnes, who lived from 1805 to 1841, acquired the chart while lieutenant in the East India Company Service and assistant to the British Resident in Kachchh. Burnes had already won celebrity through his 1832 imperial expedition across Central Asia, which had resulted in a best-selling book, honors from London learned societies including the RGS, and an audience with King William IV.

He declared it would “form a specimen of naval surveying … unequaled in any of the cabinets of Europe” and believed it had been a working document used on board ship. But he didn’t realize it was a practical navigational chart.

The chart has been interpreted previously in 1947, 1987, 2002, 2012 and 2022, but scholars have overlooked the chart’s navigational affordances. Around half of the chart’s Devanagari toponyms were left unidentified and without locations—with more still lacking precision.

Two centuries on, experts unlock secrets of Red Sea and Gulf of Aden sailing chart

Credit: University of Exeter

How the scroll guided sailors

Researchers believe they have now found coordinates for all 66 toponyms and improved transcriptions of the Devanagari script.

They have found that the chart’s 29 rhumb lines serve three main purposes: establishing the principal trend of a coastline; indicating a direction of travel across open water; and, in possibly two cases, showing safe passage into and out of port.

Professor John Cooper, from the University of Exeter’s Institute of Arab and Islamic Studies, who led the research, said, “Today we are used to maps and charts that project space mathematically and to scale, making regions of the world visually familiar and accessible to us in a very particular way. Although this chart doesn’t look accurate to our way of thinking, it allowed seafarers with the necessary experience and knowledge of stellar navigation to negotiate some of the harshest and most challenging waters in the world. All the required information was packed into a very portable scroll just 25 cm wide.

“This is a rich and effective navigational reference work. Its stellar information allowed sailors to know their latitude and set sailing directions; its many place names and topographical information enabled them to locate themselves precisely; its religious buildings suggest the navigator’s Muslim faith; and its flags suggest nodes of political and fiscal action.

“It was designed for those with specific local navigational knowledge. Although rich, the inscribed information would not be enough to enable people uninitiated in regional seafaring traditions to navigate safely. But, for those who knew, it functioned as a handy reference at sea, fulfilling a mnemonic role. Its scroll format allowed it to be opened partially, showing only the relevant section, with the rest rolled away. It was stored and handled easily on board the ship.”

Dr. Katherine Parker, the Royal Geographical Society’s Cartographic Collections Manager, said, “Re-examining our Collections is an ongoing process that allows researchers to apply new methods, technologies and perspectives, uncovering the meanings and utility that these remarkable artifacts held for the people who created them centuries ago. We have been delighted to work alongside the team to bring a greater understanding of the navigational, geographical and cultural value of this chart, as well as the cartographic skill and knowledge of its creators, into focus.”

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Provided by University of Exeter 

Who’s behind this story?

Stephanie Baum, Master’s in TESOL from The New School. Passionate about language learning and editing science news on biology and space exploration. Full profile →

Robert Egan, Bachelor’s in mathematical biology, Master’s in creative writing. Well-traveled with unique perspectives on science and language. Full profile →


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