Climate Change & You is a fortnightly newsletter written by Bibek Bhattacharya and Sayantan Bera. Subscribe to the newsletter to get it directly in your inbox.

Through August and September, the climate news around India has been dominated by the deadly floods sweeping through Punjab (and Pakistan's Punjab province), as well as the immense destruction and deaths caused by flash floods and landslides throughout the Western Himalayas. Come October and Diwali, the conversation will inevitably turn to deadly atmospheric pollution.

While it is easy to draw a direct line between excessive and violent monsoon rainfall and climate change, making a connection between climate change and atmospheric pollution is less straightforward. At the Mint Sustainability Summit earlier this month, I posed this very question to atmospheric scientist Professor Krishna AchutaRao, from the Centre for Atmospheric Sciences, IIT (Delhi). As part of his research, Professor AchutaRao uses climate models to understand how Earth's climate is affected by natural and human-made factors.

He said there is a distinct connection between rising heat and pollution, just not what you'd expect. "If you look at pictures of India taken from space, you will see a murky haze (of atmospheric pollution) all the way from Pakistan to Bangladesh. What that haze is telling us is that some of the sunlight that would have made it to the ground is being reflected back into space." As a result, India has heated up less than the global average, because of air pollution.

Of course, this doesn't mean that we shouldn't try to clean up the air we breathe. What it effectively goes to show is that human effects on vast earth systems often have unintended consequences.

Although we call climate change anthropogenic or 'human-made', the term gives us a slightly false picture. Not every person or community contributes to greenhouse gas (GHG) emissions equally. The richer Western nations, for example, emit way more per capita than Global South countries, and have been doing so for far longer. Similarly, when it comes to current emitters, as we have discussed in an earlier newsletter, the most damage is done by a handful of big fossil fuel and cement companies.

These 'Carbon Majors' are the subject of a new study published in the journal Nature that links their emissions to the greater number of heatwaves that the world is experiencing. The study, titled Systematic Attribution Of Heatwaves To The Emissions Of Climate Majors was published on 10 September. It shows that 213 major heatwaves between 2000-2023, were made more likely due to climate change, "to which each of the 180 carbon majors substantially contributed".

When it comes to Indian companies, the study maintains that just the emissions from Coal India were sufficient to contribute to global heating leading to 51 of the 213 heatwaves. This means, the study explains, that in a hypothetical world where only GHG emissions from Coal India existed, 51 heatwaves would have still happened. Similarly, individual emissions from ONGC India and Singarani Collieries would have been enough to fuel 50 heatwaves. For Adani Enterprises, that number is 31. Individual emissions from other big companies like BP, ExxonMobil, Chevron, Shell or Saudi Aramco have a similar effect on global heating.

-A vital ocean circulation current, the Atlantic Meridional Overturning Circulation (Amoc), that regulates surface temperatures in Europe, is slowing down, and will collapse unless we find a way to stop further heating. Read here why this affects us all.

-After a few months of non-stop calamities afflicting Himalayan and border states, the financial damages are piling up and revenue deficits are skyrocketing. Read here how this has caused border and hill states to ask the 16th Finance Commission for increased assistance to address disaster-related costs.

-Global warming is altering seasonal tourism patterns and changing the way people are travelling. Read here how peak seasons are flattening out, which, in some cases, is making holidaymakers happier.

One of the great white hopes of a solution to the climate crisis is the tech fantasy of geo-engineering, which I have written about in the newsletter before. A new study published in the journal Frontiers Of Science analyses the feasibility of five 'well-publicized' geo-engineering plans to re-freeze polar ice, or at least stop further melting. For context, the melting of Arctic sea ice and permafrost, as well as the steady loss of mass from the vast Greenland and Antarctic ice sheets poses a multi-pronged threat. This will lead to massive sea level rise, destroy habitats and ecologies, release methane and harmful viruses, increase heating and adversely affect ocean currents. The geo-engineering plans are untested tech fixes that hope to prevent these outcomes.

The study concludes that any attempts at polar geo-engineering not only isn't going to work, but will harm ecosystems, communities, international relations, and any hopes of the world reaching net zero GHG emissions by 2050. "These ideas are often well-intentioned, but they're flawed...deploying any of these five polar projects is likely to work against the polar regions and the planet," said the study's lead author Professor Martin Siegert from the University of Exeter. The projects would also need at least $10 billion each to set up and run.

Here's a list of the five proposals and their harmful impacts:

Stratospheric aerosol injections: This involves the release of sunlight-reflecting particles like sulphates into the stratosphere to reduce the sun's warming effect. Harmful effects: Depleting the ozone layer and changing planetary climate patterns.

Sea curtains and walls: This involves installing buoys anchored to the seabed to prevent warm water from reaching and melting ice shelves. Harmful effects: These will disrupt marine habitats, as well as the feeding grounds and migration routes of animals like whales and seals.

Pumping sea water onto sea ice (to thicken it) or scattering glass microbeads (to increase sea ice reflectivity). Harmful effects: These would require massive infrastructure, a permanent and large human presence and would severely affect local ecology.

Pumping subglacial water away from glaciers to slow ice sheet flow and ice loss. Harmful effects: This process risks contaminating such environments with fuels.

Ocean fertilization: Adding nutrients like iron to the polar ocean to encourage phytoplankton blooms. These organisms draw carbon into the deep ocean when they die. Harmful effects: This form of fertilization risks upsetting the balance of species in the region, and triggering shifts in natural chemical cycling.

What do people around the world really think of climate action, and do they approve of the need for it? This is increasingly at the heart of government action (or inaction) to stave off the worst ravages of the climate crisis. However, a comprehensive survey conducted last year showed without a shadow of doubt that people all over the world feel that climate change is a real and present threat and would want their governments to up their climate action.

For the study, researchers surveyed 130,000 people across 125 countries and asked them a set of questions, including this one: how many of them would donate a month of their earnings towards climate action. A whopping 69% of those surveyed said that they would do so. Moreover, 89% of those surveyed said that they support intensified political action, and 86% said that they would endorse pro-climate social norms.

The 89% number is also behind an international media campaign to influence world leaders to show greater urgency on climate action, as I've written in an earlier edition of the newsletter.

Robert Macfarlane is probably the best nature writer in the world right now. Ever since he debuted in 2003 with the magical Mountains of the Mind: A History of a Fascination, Macfarlane's books straddle the worlds of travel and nature writing, along with a rare ability to get to the heart of human obsessions with the natural world. His 2019 book Underland: A Deep Time Journey exemplifies this, as he visits improbable and haunting underground places around the world, from a limestone cave system in the Mendips in England to the catacombs of Paris and an underground river in Italy.

Although none of his travels in the book is explicitly about climate, in a way they all dance around the subject, by bringing to light the things hidden under the Earth's surface -- either the works of titanic geological forces, or wispy fungi networks connecting forests into living organisms. Implicit in this is also the distinctly human need to dig up what is buried -- like fossil fuels -- and the unintended consequences that this unleashes. A must-read.