In 2025, Earth Overshoot Day fell on 24 July — the date by which humanity had consumed more from nature than the planet can renew in an entire year. For Ireland, that date arrived even earlier, on 17 May. At the current rate of global consumption, we would need 1.8 Earths to sustain ourselves. These are not projections; they are a measure of where we stand today. The only framework that offers a credible path forward is sustainable development.
Sustainable development is defined in the Brundtland Report (Brundtland, 1987) as ‘Development which meets the needs of the present without compromising the ability of future generations to meet their own needs’
By this measure, we are currently doing badly. The Earth Overshoot Day initiative calculates the date on which humanity has exhausted nature’s budget for the year — based on what the planet can biologically regenerate. It computes this both globally and on a country-by-country basis, assuming the world’s entire population consumed at the level of that particular country.
Globally in 2025, that date fell on 24 July, eight days earlier than the previous year. In Ireland, it came as early as 17 May.
Meanwhile, CO2 levels continue to climb. According to the NOAA who track global GHGs at their Mauna Loa site in Hawaii, CO2 levels are now at 425.5 ppm. This is up from 318ppm since they started taking measurements in 1960. It was 280ppm in the pre-industrial era, before the burning of fossil fuels.
The last time CO2 levels were this high was 3 million years ago. Sea levels were up to 25m higher than they are today.
The Paris Agreement, signed in 2015 was a global treaty that aimed to limit global warming to 1.5°C above pre-industrial levels.
That particular aim is effectively dead in the water with indicators showing that limit has been temporarily breached in 2024 and in 2025. We are currently on course for a 2.5°C increase based on current projections. This will have devastating and far-reaching consequences for Ireland and the globe.
To achieve the Paris Agreement target of 1.5°C above pre-industrial levels, in Ireland, a 51% reduction in GHG emissions must occur by 2030 and emissions neutrality by 2050. These are legally binding targets. Failure to meet them would not result in direct EU fines, but Ireland would be required to purchase carbon credits from compliant EU member states at a cost estimated at between €7.5 billion and €26.4 billion.
At the current rate, Ireland will only achieve a reduction of up to 25% in GHG emissions by 2030, according to the EPA’s latest projections (May 2026) — far short of both the national 51% target and the EU Effort Sharing Regulation target of 42%.
But this figure could pale into insignificance compared to the cost to the national and global economy if action is not taken. According to Swiss Re, a major reinsurance provider, there were 45 natural hazard events in excess of $1 Billion in 2023, up from 17 events in 2018. The 2024 claims were 33% higher than the previous 10 year average.
Increased natural disasters from hurricanes, floods and fires have huge implications for the global economy as most wealth is held in the form of fixed assets. Increased insurance premiums and the devaluation effect of uninsurable property will be profound.
A May 2026 article in The Conversation states that;
‘As climate change makes extreme weather events more intense and frequent, “uninsurable areas” are becoming increasingly common. They are a clear demonstration that insurance – the mechanism through which modern societies deal with all kinds of risk – is structurally underprepared for this new climate era’
A January 2026 article in The New Scientist magazine, ‘Sooner Than Expected Climate Change to Cost the World Trillions’ states;
‘The impacts of climate change are occurring sooner than expected, but governments and businesses continue to underestimate the risks, which could add up to trillions of dollars in economic losses by 2050’
It goes on to say;
‘the world may have seriously underestimated the rate of warming and faces “planetary insolvency”, where global warming begins to severely damage both the environment and economic growth’
And that;
‘global GDP could fall by 25 per cent with 2°C of warming by 2050. This would mean up to $25 trillion in economic losses annually due to climate-related impacts’
The words ‘planetary insolvency’ and ‘$25 trillion in economic losses annually’ should cause alarm bells to ring at the highest levels of leadership throughout the world.
As well as the enormous human suffering and displacement that would occur, such an outcome must be avoided. The only way to do this is to keep global temperatures as close to the 1.5°C as possible.
The Legal Landscape
The Paris Climate Agreement, which aims to achieve this target, is reflected in Irish legislation in the Climate Action and Low Carbon Development Act 2021 (‘the Act’). This legislation puts in place the legislative framework that governs and overarches every element of the economy.
- The stated objective of the legislation is to “pursue and achieve … the transition to a climate-resilient, biodiversity-rich, environmentally-sustainable and climate-neutral economy by no later than the end of the year 2050.”
Interim target for 2030
- Sets a target of a 51% reduction in greenhouse-gas (GHG) emissions by 2030 (relative to a 2018 baseline) in the non-ETS sectors.
- Aligns with the government’s Programme for Government commitment and gives a mid-term milestone.
Carbon budgets & sectoral emission ceilings
- Introduces legally-binding five-year carbon budgets for the economy, beginning from 2021, with a rolling 15-year perspective (i.e., three successive budget periods visible)
- Requires the government to set sectoral emissions ceilings for relevant sectors aligned with each carbon budget.
Planning and strategy frameworks
- Annual updates of the national annual climate action plan.
- A National Long-Term Climate Action Strategy (every five years) to set out the 30-year vision for how to achieve the 2050 objective.
- A requirement for a National Adaptation Framework and sectoral adaptation plans to build climate resilience.
Local authority & public-body obligations
- Each local authority must prepare and update (at least every five years) a Local Authority Climate Action Plan including both mitigation and adaptation measures; their development plans must align with these climate action plans.
- Public bodies must act in a way consistent with the national climate objective and supporting legislation.
It is clear that the Act has ambitious and far-reaching implications for all aspects of the economy and the environment, given that our economy is largely fossil fuel driven. Not only that, it requires the environment to be biodiversity-rich and environmentally sustainable, which has significant implications for the agriculture sector.
The Policy Framework
Integrating such far reaching legislation into all aspects of government is a mammoth task. To achieve this, there is a framework of policy to help guide government departments and local authorities.
The Climate Action Plan
The primary document in this respect is now the Climate Action Plan 2025 (CAP25), approved by Government on 15 April 2025. CAP25 is the third statutory annual update under the Act and is designed to be read in conjunction with CAP24, focusing on accelerating delivery of outstanding actions and high-impact measures. CAP24, which extends to 416 pages, remains the comprehensive reference for the full suite of sectoral measures; CAP25 builds on this by setting out new priority actions for the year ahead and addressing the second carbon budget period 2026–2030.
The Climate Action Plan is designed to work in harmony with the National Development Plan 2021–2030.
Each of the 31 local authorities have prepared their own Local Authority Climate Action Plans. The 13 priority sectors identified in the 2024 National Adaptation Framework were required to complete their Sectoral Adaptation Plans by Q3 2025. The 10 plans (the 13 sectors being grouped into 10 documents) were published on 14 November 2025.
The National Adaptation Plan
These Sectoral Adaptation Plans follow the National Adaptation Framework published in 2024. This sets out how the country will adapt to the increasing effects of climate change and sea level rise.
The National Development Plan 2021-2030
The NDP sets out public investment objectives for the period from 2021 to 2030 amounting to €165 billion. In the 2025 NDP Review, this has been increased to €275 billion out to 2035. The document recognises the urgency of the environmental situation and is aligned with the Act and the Climate Action Plan.
It states; ‘The investments planned will provide for the decarbonisation of society, while meeting the needs of a population that will be 1 million larger by 2040, compared to 2016’
It goes on to require a ‘systematic climate and environmental assessment of all capital expenditure plans’
National Strategic Objective 8 (NSO 8) of the NDP deals with the Transition to a Climate Neutral and Climate Resilient Society. It recognises that ‘A radical restructuring of our society and economy will be required to reduce fossil fuel use and move rapidly to a climate neutral economic model by 2050.’
Along with decarbonisation of energy and transport, making our residential built environment energy efficient is critically important. Measures such as constructing all new houses to NZEB standards and installing 400,000 new heat pumps in existing buildings contribute to this. It is also making the retrofit of residential buildings a cornerstone of the plan.
A €500m Climate Action Fund was established to support projects that contribute to achieving the targets.
NSO 8 also includes for rehabilitation of Bord na Móna peatlands, the Celtic Interconnector, flood relief schemes and sustainable transport plans.
The Infrastructure Guidelines, Green Public Procurement Strategy and The BIM Mandate.
This triumvirate of policies is where the tangible action happens to quantify and value the operational and construction price of carbon.
In the Infrastructure Guidelines (IGs) is the management framework for public investment, issued by DPER. They replace the Public Spending Code. They determine how emissions are valued in decision making rather than prescribing construction methods. This involves applying the Shadow Price of Carbon which is calculated in Business Case Cost Benefit Analysis.
In parallel to the IGs is the Green Public Procurement (GPP) Strategy 2024-2027. This requires public bodies to specify low carbon construction materials, in particular low carbon concrete which can amount to 50% of a project’s total emissions. In order to measure this, the use of Whole Life Cycle Assessments is required to calculate carbon reductions against a ‘business as usual’ scenario
The system of how this is reported and structured is the next part of the puzzle.
The BIM mandate, introduced on a cascading scale of projects beginning at projects of greater than €100m at Stage 1 in January 2024 to projects of over €1m within a 3 year period for design teams and a 4 year period to include contractors and supply chains.
Alongside the requirement to use a structured BIM Implementation Plan in accordance with ISO 19650, there is also a requirement to measure the building’s carbon emissions. These are then reported alongside cost and life cycle costs in ICMS3 format.
ICMS3
The International Cost Management Standard 3rd revision is mandated for use across all public sector projects under the BIM Mandate. It replaces the National Standard of Building Elements (NSBE) which has been in use in Ireland since 1970.
ICMS3 provides a cost management infrastructure which includes the International Property Measurement Standard (IPMS) which contains some fundamental changes to how Gross Internal Floor Areas (GIFA) and the new Gross External Floor Areas (GEFA) are measured and the International Land Measurement Standard (ILMS).
ICMS3 covers 19 different project types: 18 are civil engineering and 1 is buildings.
The purpose of ICMS3 is to provide global consistency to track cost, carbon and lifecycle costs across different project types to be able to compare them on an equal basis across multiple jurisdictions.
It is probably one of the most fundamental changes to happen to the quantity surveying sector in a generation.
ICMS3 is a hierarchical framework comprising 4 levels:
- Level 1: Projects or Sub-Projects
- Level 2: Categories
- Level 3: Groups
- Level 4: Sub-Groups
It also allows for cost and carbon analysis across the entire lifecycle of an asset from land acquisition to end of life using the ACROME acronym which represents:
- Acquisition
- Construction Costs
- Renewal
- Operation
- Maintenance
- End of Life
This structure allows a client to compare the costs of leasing an existing building or building a new one on a comparative basis.
It is a highly integrated cost management system that provides structured cost data and allows for future digitisation.
The frameworks described above — the Act, the Climate Action Plan, the Infrastructure Guidelines, GPP Strategy, BIM Mandate and ICMS3 — represent a coherent, if demanding, architecture for change. For construction professionals, they define the new terms of practice: carbon is now a measurable, reportable cost alongside time and money. Ireland overshot its annual resource budget on 17 May 2025. The tools to reverse that trajectory exist. The question is whether those responsible for delivering the built environment will engage with them seriously — because the alternative is not the status quo, but something considerably worse.
