NI: NEW NORMAL - NEar surface Warming in the INdian Ocean and Rainfall Monsoon Anomaly Links

One of the biggest environmental challenges of our time is understanding and predicting the Earth's response to excess heating in the climate system due to anthropogenic warming. The ocean absorbs more heat than all other components of the climate system, capturing more than 90% of the excess heat. Of the global oceans, the Indian Ocean is found to be warming faster than any other ocean, accounting for 25% of the total ocean heat uptake. Countries bordering the Indian Ocean are dependent on monsoon rainfall to support their agriculture-based economies. Specifically, the agricultural sector of the Indian economy contributes about 20% of Indian GDP (https://www.oecd-ilibrary.org) but employs around 60% of the population (Economic Survey of India/Indian National Sample Survey Office). Many scientific studies show that anthropogenic warming is leading to unprecedented climate extremes, such as extremes in monsoon rainfall, and climate models project that these events will only increase in frequency and intensity in the future with massive socioeconomic impacts (e.g. 2018 flooding of Kerala in southern India was the worst in nearly 100 years, claiming the lives of ~500 people).

Scientists have mapped the general evolution of the monsoon cycle and identified the sea surface temperature (SST) of the Bay of Bengal as one of the key drivers of monsoon-related rainfall in South Asia. However, the relative importance of different processes (e.g. ocean vs atmospheric) influencing the SST and hence monsoon rainfall are not well understood, and because extreme monsoon rainfall events vary significantly from known 'average' conditions, we are not yet able to predict when extreme events will occur. NEW NORMAL aims to address these open questions by bringing together new international collaborations between the UK and world-leading authorities in Indian Ocean warming and monsoon dynamics from Indian Institutes. Their aims will be to a) quantify contributions and pathways of processes that influence Bay of Bengal SST during extreme events, b) test the predictability of the Bay of Bengal SST for lead times up to a decade with particular focus on documented past extreme events, and c) build a roadmap for an ambitious future programme which will be required to address the ongoing and accelerating impacts of climate change on the South Asian monsoon. NEW NORMAL will thus bring together the international scientific community towards understanding and predicting (what may soon be) 'the new climate normal', i.e. more numerous and more extreme climate events.

The completion of NEW NORMAL and subsequent programmes has direct applications and benefits for the economic development and welfare of India: Better predictions of monsoon onset and rainfall, which has direct benefit for the food water and energy sectors in India; Benefits due to improved prediction of monsoon onset and rainfall will be in the form of increased yields and reduced losses; timely warning of potential flooding, droughts and heatwaves will allow adaption and mitigation to ensure lower volatility in food availability and cost. Thus, more skilful prediction of the monsoon will also have economic and health benefits for the poorest in the form of reduced fluctuations in food prices and improved nutrition. Aside from the impact on agriculture, water and energy, the monsoon related flooding results in a loss of life and property and costs in India amount to huge sums annually in emergency relief rebuilding infrastructure. For example, the cost of recovery from the 2018 Kerala floods was estimated by the World Bank to be in the region of $3.6bn. This economic cost could be substantially reduced if more skilful forecasts become available.