Extreme heat is rapidly emerging as one of the world’s most lethal climate risks, with the evidence pointing to around 500,000 deaths annually. As cooling demand is projected to triple by 2050, the global development challenge is no longer just about expanding air conditioning, but about rethinking how buildings and cities stay cool. Against this backdrop, Martin Krause, Director of the Climate Division at UNEP, who was in Chennai to participate in the Tamil Nadu Climate Summit 4.0 and engage with state authorities and the real estate sector, spoke exclusively to The New Indian Express.
Excerpts:
How is UNEP currently prioritising India and where do you see the biggest implementation gaps on the ground?
India is a very important partner for UNEP. We engage primarily at the national level, but increasingly also at state and city levels because climate impacts are felt locally. India has made strong commitments on renewable energy, electric mobility and long-term net-zero pathways.
The main gaps we see are in operationalising policies on the ground — especially around climate resilience and adaptation. Awareness around extreme heat and cooling solutions is only now emerging globally, including in India. Until three or four years ago, heat was not a prominent policy issue. That is changing rapidly.
States like Tamil Nadu are emerging as key climate actors. Is UNEP rethinking its engagement to work more deeply with sub-national governments?
It is not either-or. As a UN body, our primary counterparts are national governments. They are the member states, but many climate actions, especially on cooling and urban heat, must happen at the city and state level.
So we are expanding engagement at all levels. In India, we are actively working with about eight states. Tamil Nadu is among our deepest collaborations, along with Maharashtra. Actions like building codes, urban planning and partnerships with developers can only be effectively implemented locally.
UNEP has stressed the need to catalyse private climate finance. What concrete progress has been made in mobilising adaptation and cooling finance in India?
India has accessed significant funding from global mechanisms like the Green Climate Fund and Global Environment Facility over the years. But it is true, access can be complex, slow and insufficient relative to the scale of need.
Public international grant funding will never be enough. We need smarter blending of public and private finance, domestic and international. Capital is risk-averse. If governments create stable, long-term policy frameworks, private finance will flow more easily into climate-smart investments, including cooling.
UNEP has warned that conventional air conditioning cannot be the sole answer to rising heat. How urgent is the shift toward passive cooling in countries like India?
It is extremely urgent. Conventional air conditioning alone is not a sustainable solution. It increases electricity demand and adds heat to the outdoor environment.
Globally, 3.8 billion people are already exposed to dangerous heat conditions, and 2 billion people still lack adequate access to cooling, which shows the scale of the challenge.
The first step is proper heat mapping. In Tamil Nadu, we have worked with partners to develop a granular urban heat island mapping methodology. This helps pinpoint hotspots at a micro level so responses can be targeted. The study will be published shortly. Passive cooling, through reflective roofs, shading, better materials, must become mainstream building practice.
What policy or market barriers are preventing passive cooling and climate-responsive building design from scaling rapidly in Indian cities?
The number one barrier is awareness. Recognition that extreme heat is a serious economic and health risk is still emerging globally. The second barrier is regulatory inertia. Changing zoning laws, building codes and urban planning frameworks is politically and institutionally complex. However, I must say Tamil Nadu shows unusual openness and awareness compared to many places globally. That makes progress here faster.
With heat stress disproportionately affecting low-income urban populations, how can passive cooling be deployed at scale without increasing housing costs?
This is a critical concern. Our studies show that basic passive cooling features — reflective paint, window shading, improved insulation — typically add only about 3 per cent to 4 per cent to construction costs, not the double-digit increases often feared. We are currently working with six developers across around a dozen projects in Tamil Nadu who have voluntarily integrated passive cooling. Many are absorbing the marginal upfront cost because long-term electricity savings benefit residents. Over time, occupants recover the additional cost through lower energy bills. The key is to avoid over-engineering and focus on simple, cost-effective measures.