In Kenya’s Laikipia County where temperatures can reach as high as 30 degrees Celsius, a local building technology is helping homes stay cooler while supporting education, creating jobs and improving the livelihoods and resilience of community residents, Climate Home News found on a visit to the region.
Situated in a semi-arid region, houses in Laikipia are mostly built with wood or cement blocks with corrugated iron sheets for roofing. This building method usually leaves the insides of homes scorching hot – and as global warming accelerates, the heat is becoming unbearable.
Peter Muthui, principal of Mukima Secondary School in Laikipia County, lived in these harsh conditions until 2023, when the Laikipia Integrated Housing Project began in his community.
The project uses compressed earth block (CEB) technology, drawing on traditional building methods and local materials – including soil, timber, grass and cow dung – to keep buildings cool in the highland climate. The thick earth walls provide insulation against the heat.
Peter Muthui, principal of Mukima Secondary School in Laikipia County, stands in front of classroom blocks built with compressed earth blocks (Photo: Vivian Chime)
Peter Muthui, principal of Mukima Secondary School in Laikipia County, stands in front of classroom blocks built with compressed earth blocks (Photo: Vivian Chime)
“Especially around the months of September all the way to December, it is very, very hot [in Laikipia], but as you might have noticed, my house is very cool even during the heat,” Muthui told Climate Home News.
His school has also deployed the technology for classrooms and boarding hostels to ensure students can carry on studying during the hottest seasons of the year. This way, they are protected from severe conditions and school closures can be avoided. In South Sudan, dozens of students collapsed from heat stroke in the capital Juba earlier this year, causing the country to shutter schools for weeks.
COP30 sees first action call on sustainable, affordable housing
The buildings and construction sector accounts for 37% of global emissions, making it the world’s largest emitter of greenhouse gases, according to the UN Environment Programme (UNEP). While calls to decarbonise the sector have grown, meaningful action to cut emissions has remained limited.
At COP28 in Dubai, the United Arab Emirates and Canada launched the Cement and Concrete Breakthrough Initiative to speed up investment in the technologies, policies and tools needed to put the cement and concrete industry on a net zero-emissions path by 2050.
Canada’s innovation minister, François-Philippe Champagne, said the initiative aimed to build a competitive “green cement and concrete industry” which creates jobs while building a cleaner future.
Coordinated by UNEP’s Global Alliance for Buildings and Construction, the council has urged countries to embed climate considerations into affordable housing from the outset, “ensuring the drive to deliver adequate homes for social inclusion goes hand in hand with minimising whole-life emissions and environmental impacts”.
Homes built with compressed earth blocks in Laikipia (Photo: Julián Reingold)
Homes built with compressed earth blocks in Laikipia (Photo: Julián Reingold)
With buildings responsible for 34% of energy-related emissions and 32% of global energy demand, and 2.8 billion people living in inadequate housing, the ICBC stressed that “affordable, adequate, resource-efficient, low-carbon, climate-resilient and durable housing is essential to a just transition, the achievement of the Sustainable Development Goals and the effective implementation of the Paris Agreement”.
Compressed earth offers local, green alternative
By using locally sourced materials, and just a little bit of cement, the compressed earth technology is helping residents in Kenya’s Laikipia region to build affordable, climate-smart homes that reduce emissions and environmental impacts while creating economic opportunities for local residents, said Dacan Aballa, construction manager at Habitat for Humanity International, the project’s developers.
Aballa said carbon emissions in the construction sector occur all through the lifecycle, from material extraction, processing and transportation to usage and end of life. However, by switching to compressed earth blocks, residents can source materials available in their environment, avoiding nearly all of that embedded carbon pollution.
According to the World Economic Forum (WEF), global cement manufacturing is responsible for about 8% of total CO2 emissions, and the current trajectory would see emissions from the sector soar to 3.8 billion tonnes per year by 2050 – a level that, compared to countries, would place the cement industry as one of the world’s top three or four emitters alongside the US and China.
Comparing compressed earth blocks and conventional materials in terms of carbon emissions, Aballa said that by using soil native to the area, the process avoids the fossil fuels that would normally have been used for to produce and transport building materials, slashing carbon and nitrogen dioxide emissions.
The local building technology also helps save on energy that would have been used for cooling these houses as well as keeping them warm during colder periods, Aballa explained.
Justin Atemi, water and sanitation officer at Habitat for Humanity, said the brick-making technique helps reduce deforestation too. This is because the blocks are left to air dry under the sun for 21 days – as opposed to conventional fired-clay blocks that use wood as fuel for kilns – and are then ready for use.
Women walk passed houses in the village of Kangimi, Kaduna State, Nigeria (Photo: Sadiq Mustapha)
Traditional knowledge becomes adaptation mechanism
Africa’s red clay soil was long used as a building material for homes, before cement blocks and concrete became common. However, the method never fully disappeared. Now, as climate change brings higher temperatures, this traditional building approach is gaining renewed attention, especially in low-income communities in arid and semi-arid regions struggling to cope with extreme heat.
From Kenya’s highlands to Senegal’s Sahelian cities, compressed earth construction is being repurposed as a low-cost, eco-friendly option for homes, schools, hospitals – and even multi-storey buildings.
Senegal’s Goethe-Institut in Dakar was constructed primarily using compressed earth blocks. In Mali, the Bamako medical school, which was built with unfired mud bricks, stays cool even during the hottest weather.
And more recently, in Nigeria’s cultural city of Benin, the just-finished Museum of West African Art (MOWA) was built using “rammed earth” architecture – a similar technology that compresses moist soil into wooden frames to form solid walls – making it one of the largest such structures in Africa.
In this rural Alabama community, some residents can’t flush their toilets. Developers want to build a state-of-the-art data center next door.
By Lee Hedgepeth
HAYNEVILLE, Ala.—When Alabamians marched from Selma to Montgomery in 1965 to demand voting rights for African Americans, Highway 80 became their path toward freedom.
The planet is heating up more quickly than ever before.
For decades, greenhouse gas emissions caused by human activity have been building up in the atmosphere and trapping ever-higher levels of heat.
The resulting asymmetry between incoming solar energy and energy radiated back out into space – known as “Earth’s energy imbalance” – provides a direct measure of the extent to which humans are disrupting the Earth’s climate system.
This imbalance is growing and in 2025 its 10-year average reached a record high, indicating that global temperatures could increase at even higher rates in the future.
This is among the headline findings of the latest “indicators of global climate change” (IGCC) report, published in the journal Earth System Science Data, which tracks changes in the climate system on an annual basis.
The report, now in its fourth iteration, has been produced by dozens of scientists from around the world.
In this article, we unpack the IGCC report, which explores how human activity is driving a growing energy imbalance and why monitoring systems to track global climate are so crucial.
(For more on previous IGCC reports, see Carbon Brief’s coverage in 2023, 2024 and 2025.)
Greenhouse gas emissions remain at an all-time high
Global greenhouse gas emissions are continuing to increase, mostly as a result of the use of fossil fuels. However, deforestation, agriculture and industrial processes also play an important role.
Glossary
CO2 equivalent: Greenhouse gases can be expressed in terms of carbon dioxide equivalent, or CO2e. For a given amount, different greenhouse gases trap different amounts of heat in the atmosphere, a quantity known as the global warming potential. Carbon dioxide equivalent is a way of comparing emissions from all greenhouse gases, not just carbon dioxide.
CO2 equivalent: Greenhouse gases can be expressed in terms of carbon dioxide equivalent, or CO2e. For a given amount, different greenhouse gases trap different amounts of heat in the atmosphere, a quantity known as… Read More
Over the most recent decade (2015-24), emissions stood at the equivalent of 54.6bn tonnes of carbon dioxide equivalent (GtCO2e) per year. In 2024, the most recent year for which we have complete data, emissions reached 56.8GtCO2e.
As the chart below shows, these emissions have pushed up atmospheric levels of CO2, methane and nitrous oxide. In 2025, concentrations of these gases reached 425.6 parts per million (ppm), 1936.3 parts per billion (ppb) and 339.4ppb, respectively.
This represents a rise of 3.8%, 3.8% and 2.2%, respectively, since the 2019 levels reported in the IPCC’s sixth assessment report (AR6).
Atmospheric concentrations of CO2 (yellow), methane (blue) and nitrous oxide (green) over 2000-25. The grey-shaded region represents continuing changes since AR6. Note the different vertical scales for each gas. Credit: Forster et al. (2026)
At the same time, declines in emissions of aerosols such as sulphur dioxide, partly as a result of efforts to tackle air pollution, are increasing the Earth’s energy imbalance. This is because aerosols have a cooling effect on the Earth’s climate, counteracting warming from CO2 and other greenhouse gas emissions.
(Tackling sulphur dioxide, alongside other particulate emissions, remains critical because the immediate health and environmental damage they cause far outweighs their short-term cooling effect on the climate.)
The Earth’s energy imbalance is rising rapidly
The Earth’s energy imbalance has long been recognised as a key indicator of how the climate is being affected by human activities.
However, it is only in the last few decades that scientists have been able to record temperature changes deep enough in the ocean to accurately quantify it.
Earth’s energy imbalance measures how quickly excess heat is accumulating in every part of the Earth system, primarily in the ocean, but also in land, ice and atmosphere.
Through this accumulation of heat, the energy imbalance influences the rate of sea level rise and ice melt across the world, as well as increasing the frequency and intensity of extreme weather events, such as storms, floods and droughts.
Without human influence, the Earth’s energy imbalance would be close to zero.
But, as greenhouse gas emissions have built up in the atmosphere, the imbalance has been growing since the 1970s. Recent increases to Earth’s energy imbalance have outpaced those projections made by climate models — indicating the planet could see more warming than expected in the future.
As the right-hand chart below shows, the imbalance is now at a record high, having more than doubled over the past two decades.
It has increased by around 40% since 2019, from an average 0.79 watts per square metre (Wm2) over 2006-18, according to IPCC AR6, to 1.12Wm2 over 2013-25.
The left-hand chart shows how heat is accumulating in the ocean (blues), ice (grey), land (orange) and atmosphere (purple).
Left: Observed changes in the Earth heat inventory for the period 1971-2020. Right: Estimates of the Earth energy imbalance for successive overlapping 20-year periods and the most recent decade (right). Shaded regions indicate the very likely range (90-100 % probability), while the stars show the CERES (NASA Clouds and the Earth’s Radiant Energy System) estimates for comparison. Credit: Forster et al. (2026)
Global temperature rise
The excess heat building up in the climate system from the energy imbalance is pushing up global temperatures at a record rate of 0.27C per decade.
We estimate that human-induced warming – the amount of observed global surface
temperature increase attributable to both the direct and indirect effects of human activities – reached 1.37C in 2025. This has risen from 1.0C in 2017, as reported in IPCC AR6.
While natural variability in the climate system – such as El Niño or La Niña events – can also influence temperatures year-to-year, the upward temperature trend we are seeing is being driven by the persistent imbalance in energy.
This is significant because 1.5C has been identified as the critical dividing line between manageable climate risks and catastrophic, potentially irreversible damage to global ecosystems and human societies.
Heat accumulating throughout the Earth system
While heat is accumulating throughout the Earth system, it is not being distributed evenly around the globe.
Since the 1970s, around 90% of this heat has been taken up by the ocean, affecting marine ecosystems, ocean circulation patterns, sea level rise and climate extremes.
For example, the number of marine heatwave days – periods of unusually high sea surface temperatures – has more than tripled globally since the early 1990s. The year 2025 alone saw 65 days of marine heatwaves – meaning they occurred, on average, more than one day a week.
Meanwhile, the cryosphere – the portion of the Earth made up of frozen water, including glaciers, ice sheets and permafrost – is experiencing widespread ice loss and thawing in response to the growing energy imbalance. This affects ecosystems, sea level rise and infrastructure in polar and high-latitude regions.
Rapid warming has also resulted in record extreme temperatures over land, with average maximum temperatures for any single day over 2016-25 around 1.92C above pre-industrial levels). This is an increase of almost half a degree compared to the previous decade (2006-15).
Sea level rise and the energy imbalance
Sea level rise provides one of the clearest long-term signals of a changing planet.
It is closely linked to Earth’s energy imbalance. As heat accumulates in the ocean, water expands, raising sea levels. Meanwhile, a warming land and atmosphere means addition of water to the oceans through melting of glaciers and ice sheets, also adding to sea level rise.
Over the long-term, sea levels have been rising, on average, at a rate of around 1.8mm per year since 1901, totalling a record 23cm in 2025. This is increasing the risk of coastal flooding, erosion and habitat loss in many low-lying areas around the world.
This rise can be seen in the left-hand chart below, which shows observed global sea level changes from tide gauges (grey and blue dashed lines) and satellites (red dashed lines) since 1901. The solid lines indicate the average across multiple datasets.
Sea level rise is accelerating consistent with the observed increase in Earth’s energy imbalance. Over 2006-25, sea levels have risen at a rate of 3.67mm per year – more than double the rate of 1.69mm per year seen over 1976-95.
This increasing rate is shown in the right-hand figure below, which shows four successive overlapping 20-year periods and the most-recent decade.
(Last year’s transition from El Niño to weak La Niña conditions affected global rainfall patterns and led to a small and temporary fall in global average sea level in 2025. This explains the slight decrease in rate of sea level rise for the most recent decade, which is affected more than the 20-year period 2006-25.)
Left: Global average sea level rise over 1901-2025, relative to a 1995-2014 baseline. Individual timeseries are shown with dashed lines, while the black solid line shows the average (from tide gauges and satellites) used in AR6 and the solid red line shows the 1993-2025 average from satellites. Right: Global mean sea-level rates (in mm per year) for four successive overlapping 20-year periods and the most-recent decade. The shading indicates the very likely range. Credit: Forster et al. (2026)
The bigger picture
Despite greenhouse gas emissions not increasing as rapidly as in the 2000s, this year’s IGCC findings continue to show how far and how fast the climate is changing due to human activity.
A significant increase in decarbonisation efforts in the second half of this decade is required to slow down the rate of human-caused warming and limit the escalation of climate risks and impacts.
These findings, like many others produced by scientists across the globe, rely on international expertise, partnership and the maintenance and availability of global climate datasets and the global observing programmes that underpin them.
This year’s edition of IGCC used more than 40 global datasets produced by research teams around the world, including the NASA satellite record of the Earth’s energy imbalance and the ARGO deep ocean float network.
However, a number of long-term monitoring programmes could be threatened by funding decisions made by governments around the world, most notably the Trump administration in the US.
Local meteorological data and weather balloon measurement programmes in many countries have declined in recent years, especially in Africa, the west Pacific and South America. This reduces scientists’ ability to monitor and understand key indicators of climate change.
This is not just an issue for climate science. Many of these observations are key to weather forecasts and systems that provide early warning for extreme weather. For example, media reports have suggested that recent reductions in weather balloon measurements in Alaska led to a lack of warnings for a recent winter storm.
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