Climate emergency: Govt must assess impact, explore worst-case scenarios

Climate scientists are generally not alarmists and very conservative, especially since there are strong and well-funded lobbies against climate change.

However, now after experiencing unprecedented and extreme climatic events such as extreme heat waves, floods, droughts, storms and forest fires, journalists and TV news readers have started using the phrases such as “climate catastrophe”, “climate emergency”, “climate apocalypse” and “disastrous climate change”.

News readers have started linking weather extremes to climate change, though scientists are a bit hesitant to say so directly, even as scientific evidence is growing linking recent extreme events to climate change. Heat stress events are given names similar to cyclones to create awareness in the population on the impending extreme events. Athens in Greece even has a dedicated ‘Chief Heat Officer’ to find ways to manage the impacts of extreme heat waves.

The Paris Agreement aims at stabilising global warming at less than 1.5 degrees Celsius, which would require deep greenhouse gas reductions from mainly burning coal, petroleum products and natural gas used in electricity generation, transport and industries by 2030 and 2040.

Further, net emissions should reach zero by around the middle of the century. Many countries have announced target years for net-zero emissions: European Union by 2050, China by 2060 and India by 2070.

Imagine, if we have to completely stop using coal or natural gas-based electricity and use only renewable electricity, shift completely to electric automobiles, produce cement and steel with no fossil fuels. All this looks difficult requiring complete transformation of energy systems. This requires trillions of dollars of investment, access to green technologies, and even development of new, cheaper technologies such as green hydrogen and steel.

Thus, according to many experts and modelers, we will not be able to hold global warming to less than 1.5 or even 2 degrees Celsius, and the world could be in very dangerous territory of over 3 degrees Celsius mean warming. The Ukraine war has threatened even modest efforts by disrupting natural gas supply, which is a less polluting fuel than coal.

The global mean warming has only touched 1.2 degrees Celsius and we are already seeing unprecedented and damaging weather events such as heat stress, floods, droughts, forest fires in every corner of the world. So far, scientific assessments have been carried out largely focusing on the potential adverse impacts of global warming at 1.5 or 2 degrees Celsius.

Even the UN Intergovernmental Panel on Climate Change (IPCC) has largely focused on assessing the impact of 1.5 to 2 degrees Celsius mean warming on human society and nature, based on the published scientific literature. In India, even studies on the impact of 1.5-2 degrees Celsius warming on different crops, rivers, forests, vector borne diseases and coastal areas are very limited, especially at state and district level.

A new study published in the prestigious journal Proceedings of National Academy of Sciences has highlighted that the impact of global mean warming of 3 or 4 degrees Celsius is not well understood. A warming of 4 degrees Celsius could be termed as potentially one of the worst-case scenarios.

The study even raises the question: could anthropogenic climate change result in worldwide societal collapse or even eventual extinction of human species? It also talks about how multiple climatic extremes such as drought and high temperature could interact with degraded natural resources, war and inequitable development.

And how the current degraded state of natural resources such as declining soil quality or ground water availability could interact with climate extremes whose combined impacts could be multiple times higher than the impact of a single climatic extreme such as drought or flood.

This study highlights that climate change could become catastrophic and calls for climate change endgame research, where levels of global warming and vulnerability of the society and nature could probably lead to climate change becoming an extinction threat.

Some scientists have concluded warming of 6 degrees Celsius could threaten the existence of human species. The UN Secretary-General is already calling climate change an “existential threat”. Climate change could directly trigger other catastrophic risks such as international conflicts or exacerbate infectious disease spread or massive migration.

Extreme temperatures combined with high humidity can negatively affect outdoor worker productivity, yields of major cereal crops and long-term health impact. The latest UN-IPCC report concludes that 50 to 75% of the global population could be exposed to life-threatening climatic conditions by the end of the century due to extreme heat and humidity.

The World Health Organisation also has warned that climate change “threatens to undo the last 50 years of progress in development, global health and poverty reduction”.

In India, a large proportion of the population is already exposed to high temperatures and large areas are exposed to frequent floods, droughts, hurricanes and cyclones. There is little research at national, state and district level on the impact of such climate change extremes on crop yields, biodiversity, forests, water resources, health, fisheries etc.

Given that a large population is exposed and vulnerable to climate risks, India should undertake a dedicated national level assessment of climate change on various sectors, regions, production systems, ecosystems, infrastructure and population categories in the short and long term.

The US, the UK and many other countries have such national level climate change impact assessments done periodically as science progresses.

Surely, the government of India and Karnataka can afford to set up a long-term institutional arrangement to conduct periodic assessment of climate change impacts and develop adaptation plans and strategies at the state and district level.

We should explore even the worst-case scenarios of global warming to understand how humans and nature will be impacted. For the first time, there is even talk of extinction of human species under some scenarios of warming. Thus, it is a wakeup call for policy makers, scientific communities and even citizens.

(The author is a retired professor, Indian Institute of Science, and a climate change expert)