London, (Samajweekly) Limiting global warming to 1.5 degrees Celsius can help identify the hotspot regions for climate change risk in the future and reduce its effects on humans by 85 per cent, finds a study.
The study, led by the University of East Anglia (UEA) researchers, calculates reductions in human exposure to a series of risks — water scarcity and heat stress, vector-borne diseases, coastal and river flooding — that would result from limiting global warming to 1.5 degrees Celsius rather than 2 degrees Celsius or 3.66 degrees Celsius.
Effects on agricultural yields and the economy are also included.
Researchers from the UK, including scientists from UEA and the University of Bristol, and from PBL Netherlands Environmental Assessment Agency, find that the risks are reduced by 10-44 per cent globally if warming is reduced to 1.5 degrees Celsius rather than 2 degrees Celsius.
However, risks will be greater if global warming is greater. The risks at 3.66 degrees Celsius warming are reduced by 26-74 per cent if instead, warming is kept to only 2 degrees Celsius. They are reduced even further, by 32-85 per cent, if warming can be limited to just 1.5 degrees Celsius. The ranges are wide because the percentage depends on which of the indicators, for example human exposure to drought or flooding, are being considered.
The findings, published in the journal Climatic Change, suggest that in percentage terms, the avoided risk is highest for river flooding, drought, and heat stress, but in absolute terms the risk reduction is greatest for drought.
The authors also identify West Africa, India, and North America as regions where the risks caused by climate change are projected to increase the most with 1.5 degrees Celsius or 2 degrees Celsius of average global warming by 2100.
The study follows the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report, which finds that global net zero CO2 emissions must be reached in the early 2050s to limit warming to 1.5 degrees Celsius with no or limited overshoot, and around the early 2070s to limit warming to 2 degrees Celsius.
“Our findings are important because the Paris Agreement target is to limit global warming to awell below’ 2 degrees Celsius and to apursue efforts’ to limit it to 1.5 degrees Celsius. This means that decision makers need to understand the benefits of aiming for the lower figure,” said lead author Prof Rachel Warren, of the Tyndall Centre for Climate Change Research at the UEA.
“While there are a number of planned additional actions to reduce emissions further, potentially limiting warming to 1.8 degrees Celsius in the most optimistic case, these still need to be delivered and further additional action is needed to limit warming to 1.5 degrees Celsius,” she added.