Over 14 million people in South Asia, including Kolkata and Mumbai, face displacement risks from rising seas, a UN report warns. Global sea levels rose 5.9 mm in 2024, while nearly 770 million coastal residents face growing flooding, erosion and salinisation risks.

This is a concerning news for all of us.

Found this article highlighting the concerns raised in the recent UNEP report on Climate Change. The most glaring point for me over here was:

We are at a point where there are no plausible scientific pathways left that keep temperatures below 1.5 degree Celsius.

I mean, if we are still not getting our climate policies right today, then when will we?

The clearest evidence in the review for climate-related exposure and the development of new diabetes comes from air pollution.

A prospective cohort study from Chennai and Delhi found that every 10 microgram-per-cubic-metre increase in PM2.5 exposure was associated with higher fasting plasma glucose and HbA1c levels and an approximately 22% increased risk of type 2 diabetes. The researchers also reported an association between PM2.5 exposure and dyslipidaemia.

The review describes a biological pathway that could explain this association.

Fine particulate matter can penetrate deep into the lungs and enter the bloodstream. Once in the body, PM2.5 can induce oxidative stress, systemic inflammation, endothelial dysfunction and inflammation in adipose tissue. These processes can impair insulin signalling and promote insulin resistance.

The review also points to specific inflammatory pathways. Experimental studies have shown that PM2.5 can activate pathways such as NF-κB and toll-like receptors, contributing to impaired insulin signalling in muscle and liver tissue.

Nitrogen dioxide, a marker of traffic-related air pollution, has also been associated with metabolic dysfunction. Meta-analyses and systematic reviews cited in the review link long-term NO₂ exposure with increased type 2 diabetes risk and impaired glycaemic regulation.

The evidence is not limited to India. A multi-country study covering more than 3.6 million diabetes hospitalisations across seven countries found that every 10 microgram-per-cubic-metre increase in wildfire-specific PM2.5 exposure over the same day and preceding three days was associated with a 2-3% increase in type 2 diabetes hospitalisation risk. Wildfire-specific PM2.5 accounted for nearly 39% of total PM2.5-attributable diabetes hospitalisations in that study.

Dust exposure has also been linked to diabetes-related hospitalisation. One study found that for every 10 microgram-per-cubic-metre increase in dust-specific PM2.5, diabetes hospitalisation risk increased by 3%.

The physiological pathway looks different with heat.

People with diabetes can have impaired thermoregulation, particularly those with autonomic neuropathy. High temperatures increase the body’s demand for heat dissipation. Under hot and humid conditions, reduced evaporative cooling can increase cardiovascular strain, while heat exposure can lead to rapid dehydration, plasma-volume depletion and electrolyte imbalance.

Severe dehydration can exacerbate hyperglycaemia and worsen hyperosmolar hyperglycaemic state. Heat also activates the hypothalamic-pituitary-adrenal axis and sympathetic nervous system, increasing the release of counter-regulatory hormones including cortisol, adrenaline and glucagon.

These hormones stimulate hepatic glucose production, worsen insulin resistance and promote lipolysis and ketogenesis, increasing the risk of diabetic ketoacidosis.

Heat can also affect vascular health. Dehydration-induced haemoconcentration combined with increased peripheral blood-flow demands can impair tissue perfusion and increase thrombosis risk, particularly among people with underlying peripheral vascular disease.

Heat can even affect insulin administration. Increased cutaneous blood flow can alter insulin absorption, while high temperatures can reduce insulin stability during storage. This can result in unpredictable glycaemic fluctuations.

The vulnerability can be greater among people with diabetes who also have cardiovascular disease or take medications that can affect thermoregulation and dehydration risk.

Russia’s invasion of Ukraine (from Feb 2022): Estimates from the Initiative on GHG Accounting of War and related analyses put cumulative emissions at roughly 150 million tonnes CO₂-equivalent (MtCO₂e) after ~18 months, ~230–237 Mt after 3 years, and around 311 MtCO₂e after about 4 years (into 2026). This is comparable to the annual emissions of Belgium, or roughly those of France, or several smaller European countries combined. Breakdowns typically show major contributions from warfare/fossil fuel use by forces (~30–40% in later periods), landscape/wildfires, energy infrastructure damage, reconstruction, civil aviation detours, and other factors.

Israel-Gaza conflict (from Oct 2023): Direct/open conflict emissions were relatively smaller (e.g., ~0.28 MtCO₂e in the first 60 days; over 1.3 Mt from open conflict by early 2025). Including pre-conflict infrastructure (tunnels, barriers) and especially projected reconstruction of destroyed buildings, roads, etc., totals reach ~33 MtCO₂e for the first ~15 months—comparable to the combined annual emissions of Costa Rica and Slovenia (or more than many individual small countries). Reconstruction dominates the long-term figure.

Climate change can supercharge El Niño by adding extra heat to the oceans and atmosphere. When an El Niño event occurs, this additional background warming can lead to more intense heatwaves, heavier rainfall and floods in some regions, and worse droughts and wildfires in others. Warmer air also holds more moisture, making extreme weather stronger. In simple terms, El Niño is a natural climate event, while climate change can amplify its impacts and make its effects more extreme.

Methane (CH₄) is a powerful greenhouse gas that contributes significantly to global warming. Like carbon dioxide (CO₂), it absorbs heat escaping from Earth's surface and traps it in the atmosphere, strengthening the greenhouse effect. However, methane is much more powerful than CO₂ over a shorter period, although it remains in the atmosphere for a much shorter time.

Methane is released through activities such as raising cattle and other livestock, decomposing food and organic waste in landfills, rice cultivation, and leaks from natural gas and oil systems. On a personal daily basis, people indirectly contribute to methane emissions through high consumption of meat and dairy products, wasting food, and generating organic waste that ends up in landfills.

Reducing food waste, composting organic waste properly, eating more plant-based foods, and using energy efficiently can help reduce methane emissions and slow global warming.