And yet, when you look closely at many of our most consequential decisions, it is hard to escape the sense that we are still behaving as if the underlying physics of climate change does not quite apply. Climate change is driven by cumulative emissions – the total amount of carbon dioxide we add to the atmosphere over time, and by the absolute level of methane emissions. This basic fact is why Ireland’s climate law is built around carbon budgets: legally binding limits on the total cumulative emissions we can produce over defined periods. Carbon budgets are how the law of physics is operationalised in policy – they are not political slogans. The Intergovernmental Panel on Climate Change has put it plainly: every bit of warming matters, every year matters, and every choice matters.

Source: The Irish Times January 01, 2026 15:06 UTC