As in Kerala, local climate processes can worsen climate extremes | Analysis Premium

If we are to improve climate models’ ability to predict extreme events more accurately, we need to fully understand the effects of local drivers that could exacerbate the climate’s effects.

At no place on the earth is the climate risk zero — yet when natural hazards strike, the resulting loss of lives, livelihoods, and assets sting. Disaster management and recovery play a crucial role in alleviating the pain. Unfortunately, however, a blame game may follow asking whether early warnings could have averted the tragedy.

Any early warning that may have been issued will always start with the weather forecast for the area where the hazard manifested. Proactively mitigating disasters instead of always managing them after they happen requires climate risk outlooks that go out to a decade or longer.

Further, post-facto analyses of deadly disasters — like the landslides in Wayanad, Kerala, on July 30 — often do not appreciate the fact that broad warnings of risks can hardly be translated to specific actions. For example, if we declare the entire Western Ghats to be vulnerable to landslides, governments can develop and enforce regulations to protect the whole range from deforestation, development, monoculture plantations, etc.

However, doing so will mitigate some landslides; it won’t get rid of extreme events induced by climate change anytime soon. Some landslides will occur anyway even if the Ghats enjoy the fullest protections from human perturbations because the risk is never zero.

Similarly, the predictions of models will also always be imperfect. If we are to improve their ability to predict extreme events more accurately (in terms of their location and amplitude), we need to fully understand the effects of local drivers that could exacerbate the climate’s effects. After every extreme event, someone claims global warming is a contributor — yet the relationship between local events and global warming complicates the truth of such claims.

The drivers of climate extremes originate from a far-away place but are usually exacerbated by some regional, location-specific factors.

For instance, a 2015 study (which included this author) indicated that coastal sea surface temperatures have a strong influence on heavy rain along India’s west coast. Wayanad district lies about 80 km from this coast. Monsoon winds stream across the equator and continue to load up on moisture as they turn southwesterly and head towards the Western Ghats. As they approach the coast, the winds sense they will have to climb the Western Ghats and slow down. Slower winds reduce the evaporation over the coastal ocean and the coastal waters tend to warm up — and warm waters exert a strong control on the atmosphere and rainfall.