If governments across the world align their 2025 climate targets with the 1.5°C limit in the Paris Agreement, they can still halve the crushing GDP losses that will otherwise hit tropical economies by 2100, and significantly mitigate sea level rise and extreme heat events, Climate Analytics concludes in a new study.
But if countries carry on with their inadequate response to the climate crisis, extreme sea level rise and major GDP losses in those regions will continue for decades and centuries to come, the think tank says.
For the study published earlier this month in the journal Earth System Dynamics, Climate Analytics researchers took governments' current Paris Agreement pledges, or Nationally Determined Contributions (NDCs), and analyzed the expected severity of climate impacts under two scenarios: mere recycling of 2020 targets, which would produce only incremental change beyond the 33% reductions by 2030 in the current NDCs, and "transformative improvements" compatible with the 1.5°C pathway, which would entail a 50% emissions reduction.
"If governments simply recycle their current emission reduction plans, as some have indicated, and they continue at that same slow pace until 2100, tropical countries could see around 60% reduction of their Gross Domestic Product," said lead author Andreas Geiges.
Other profound harms springing from that inadequate response to the climate crisis include 10% of the global land area suffering "extreme hot days more than 4°C warmer than in the recent past," and two metres of locked-in sea level rise by 2300.
But those cataclysmic damages can yet be avoided. Geiges and his fellow researchers found that a global effort to make NDCs compatible with the 1.5°C limit would see both GDP harms and sea level rise risk halved, and the worst extremities of heat avoided.
The authors of the new study also warn that transformative action by bigger emitters like China, the major European economies, and the United States will not be sufficient to set the world on the path to 1.5°C.
"Our results show that while big emitters should spearhead global efforts, transformational change to achieve the goals of the Paris Agreement needs all hands on deck," said co-author Carl-Friedrich Schleussner.