A University of Melbourne team has quantified what climate justice advocates have argued for decades: the regions least responsible for greenhouse gas emissions bear the most warming, and reaching net zero will not reverse that inequality. The study, published in Environmental Research Letters, modelled temperature trajectories under net-zero and net-negative emissions scenarios, overlaid them with GDP data, and found the gap between tropical and higher-latitude warming persists indefinitely under net zero. Only active carbon drawdown — net-negative emissions — begins to close it, and even then over "many decades." The mechanism is straightforward. Tropical regions have already warmed more relative to their historical baselines than wealthier nations at higher latitudes. That differential is a product of atmospheric physics and geography, not policy — but the policy response locks it in. Under a net-zero pathway that merely stops adding carbon, the accumulated warming continues for centuries. The carbon already emitted is doing its work. Getting to net zero faster limits the long-term overshoot, but does not eliminate it. Dr Andrew King, the lead author, made the structural point bluntly: "The wealthier countries that have caused more of the problem are not those that are the most exposed, even beyond net zero." Tropical ecosystems evolved within narrower temperature bands. Coral reefs, already collapsing, face continued stress long after emissions peak. The damage curve for the tropics has a much longer tail than for temperate regions. The research arrives alongside a UN refugee agency report linking climate damage to statelessness. An estimated 4.5 million people are currently stateless — almost certainly an undercount — and climate-driven displacement from fire, flood, and sea-level rise is increasing that number. Pacific island nations losing land to rising seas face existential questions about the continuity of statehood itself. The report, co-produced with the Peter McMullin Centre on Statelessness at the University of Melbourne, recommended digitising citizenship records and ensuring children can inherit nationality from mothers, not just fathers. The two reports together illustrate a single structural problem: the costs of the climate crisis are borne by people and nations with the least capacity to absorb them, the least responsibility for creating them, and the least political power to change the trajectory. Wealthy emitters capture the benefits of fossil-fuelled growth; tropical nations absorb the temperature overshoot and the displacement. Net zero, as currently framed, stabilises the system at a point that is already deeply unequal. The policy implication is uncomfortable. Net zero is necessary but insufficient for climate equity. Without net-negative emissions — active carbon removal at scale — the inequality is permanent. And net-negative technologies remain unproven at the scale required. The Paris Agreement's implicit goal of net zero was a political achievement; the physics says it locks in a world where the poorest stay hottest for centuries. None of this is speculative. The modelling uses three independent climate simulation ensembles. The GDP overlay is standard. The finding is that the structure of atmospheric warming, combined with the geography of poverty, produces an inequality that policy must actively reverse — not merely halt. Stopping the bleeding is not the same as healing the wound.
