Current Climate Pledges Put World on Track for 2.48C by 2300 - 0.48C Above the Safety Threshold

The Paris Agreement set two temperature targets: limit global average warming to well below 2 degrees Celsius above pre-industrial levels, and pursue efforts to hold it to 1.5 degrees. More than 190 countries signed on. The question that has followed ever since is whether the actual emission reduction commitments those countries submitted are consistent with reaching either goal.

A study published in Environmental Science and Policy (Volume 174, December 2025) by Assistant Professor Taeyoung Jin of Jeonbuk National University and colleagues from Pusan National University uses an integrated assessment model to project how current pledges translate into long-run temperature outcomes - and the numbers do not close the gap.

The Model and What It Projects

The analysis used the Regional Integrated Model of Climate and the Economy, or RICE-2010, which simulates feedback loops between economic growth, carbon emissions, climate change, and economic damage from climate impacts across distinct global regions. The researchers built four scenarios into the model: a business-as-usual trajectory with no emission cuts; a social optimum maximizing global welfare; a net-zero scenario based on actual national commitments including 2030 targets and long-term net-zero pledges; and a 1.5-degree-compliant pathway.

Under business-as-usual, the model projects up to 7 degrees Celsius of warming by 2300 - the high end of what climate models consistently indicate as the consequence of unconstrained fossil fuel use. The net-zero scenario, incorporating current pledges, limits warming to approximately 2.48 degrees Celsius. Progress relative to a no-action baseline is substantial. But it falls short of the 2-degree threshold by nearly half a degree - a gap that has real consequences.

What the 0.48-Degree Gap Costs

The study estimates total global climate-related economic damages could reach nearly $65 trillion by 2200 under business-as-usual. Under the current pledges scenario, that figure drops to roughly $19 trillion. A pathway aligned with 1.5 degrees reduces it further to approximately $15 trillion. The $4 trillion difference between the 2.48-degree and 1.5-degree outcomes represents the economic cost of the gap between current ambition and sufficient ambition.

Closing that gap, the researchers calculate, requires an additional approximately 5 gigatonnes of CO2-equivalent emission reductions annually by 2030, beyond what current national commitments already incorporate. For context, global annual CO2 emissions from energy and industry are currently around 37 gigatons. A 5-gigaton additional reduction represents roughly 13% of current emissions - a large but not unprecedented policy target.

"Even if every country keeps its current promises to cut carbon emissions, the world is still on track to warm by about 2.5 degrees, which is higher than the internationally agreed 2-degree safety limit," said Dr. Jin. "If countries act earlier and more decisively, the overall damage from climate change can be significantly reduced, even if it requires short-term economic adjustments."

The Model's Constraints

The RICE-2010 model is a useful tool for long-horizon policy analysis but comes with substantial uncertainty. Economic damage functions - the relationships between temperature increase and economic output loss - are estimated from historical data and empirical studies, but their accuracy degrades at higher temperatures and longer time horizons. Projecting out to 2300 requires assumptions about technology change, demographic shifts, and economic structures that cannot be reliably made centuries in advance.

The model also uses regional aggregations that smooth over large within-region differences in climate vulnerability. Some countries and communities will experience damages far above the global averages these projections report; others will experience less. The net-zero scenarios also assume full implementation of current pledges - a historically optimistic assumption given the track record of emissions commitments.

The study's value is in establishing a quantitative benchmark: at current ambition, the world warms to approximately 2.5 degrees, not 2, and the difference in projected damages runs to trillions of dollars. Those numbers provide a clear target for the magnitude of additional action required, and a reference point against which future national pledge updates can be measured.