Knowledge Nugget | ‘Limiting Overshoot’: What does latest UN report warn about?

2. But even in the best case scenarios the temperature rise is expected to go up to at least 1.8 degree Celsius before declining. Most other pathways project peak temperatures to exceed 2 degree Celsius over pre-industrial times.

3. “We are at a point where there are no plausible scientific pathways left that keep temperatures below 1.5 degree Celsius,” the report said.

4. This is the first time that an authoritative report has acknowledged that a breach of the 1.5 degree Celsius threshold is now inevitable.

5. Most other reports and analyses, including those by the Intergovernmental Panel on Climate Change (IPCC), have always offered a narrow, though ever-shrinking, window of opportunity to keep temperature rise within this limit.

Why is the 1.5°C target significant?

6. The safer 1.5 degree Celsius limit was chosen based on a fact-finding report, which found that breaching the threshold could lead to “some regions and vulnerable ecosystems” facing high risks, over an extended, decades-long period.

7. The lower threshold matters because climate risks increase with every additional fraction of a degree of warming. The 1.5°C limit was never considered a completely “safe” level of warming, but staying closer to it reduces the severity of risks to people and ecosystems.

8. For years, 2°C was the threshold widely used to assess dangerous climate change. Yale economist William Nordhaus first suggested that if global warming were to exceed 2°C, climate change would push living conditions outside the range experienced by human civilisation. 

9. Over time, scientists and policymakers increasingly used 2°C as an organising principle for climate action. It was only with the Cancun Agreements, signed at the UN Climate Change Conference (COP 16), that both 2°C and 1.5°C were formally written into an international climate accord. 

10. The 2015 Paris Agreement, signed by 193 countries and the EU, established 2°C as the upper limit while identifying 1.5°C as the more desirable goal, because the risks of extreme heat, drought, water stress and other climate impacts are substantially lower at 1.5°C than at 2°C. 

11. Under Article 2 of the agreement, nations must commit to keep global average temperatures well below 2°C above pre-industrial levels, and ideally capped at 1.5°C.

12. This does not mean that limiting warming to 1.5°C is “safe”. The report notes that climate impacts intensify as warming rises, with growing risks of irreversible changes such as Amazon dieback, permafrost thaw and ice-sheet collapse. 

What happens if the 1.5 degree threshold is breached? 

1. The 1.5 degree Celsius threshold is not a light switch which, if turned on, would trigger a climate apocalypse.

2. It is set as a “defence line”, to ensure that the world avoids the disastrous and irreversible adverse effects of climate change which would begin to unfold once the average temperature increases by 2 degree Celsius above the pre-industrial levels. 

3. Overshooting 1.5°C will still cause harmful, long-lasting damage, even if temperatures are eventually brought back down. The report notes risks involving the Greenland and West Antarctic ice sheets, the Amazon rainforest, and the Atlantic Meridional Overturning Circulation, a major system of ocean currents that helps regulate climate.

4. The further temperatures rise above 1.5°C, the harder and more expensive it also becomes to bring them back down, increasing reliance on carbon dioxide removal in addition to emissions cuts.

5. Recent incidents show that climate impacts already unfolding — including extreme weather events, floods, droughts, heatwaves and wildfires — are expected to become more severe and frequent as global warming increases.

6. Ajay Mathur, former director general of International Solar Alliance and a former climate negotiator for India, said the recent disaster in Nepal was another grim reminder of the kind of risks that are likely to get enhanced if temperatures are allowed to continue to rise.

7. Severe heatwave over North and Central India in late May in 2024, which saw temperatures nearing 50 degree Celsius in Delhi and Rajasthan, was nearly 1.5 degree Celsius warmer than past heatwaves. 

8. In April 2024, the US National Oceanic and Atmospheric Administration (NOAA) said the fourth global mass coral bleaching event has been triggered by extraordinarily high ocean temperatures. This could harm ocean life, and the lives of millions of people who rely on reefs for food, jobs, and coastal defence.

9. In 2023, a report found that five major climate tipping points are already at risk of being crossed due to warming. Climate tipping points are critical thresholds beyond which a natural system can tip into an entirely different state. They cause irreversible damage to the planet, including more warming.

10. Scientists have identified a number of these tipping points across Earth, which fall into three broad categories: cryosphere (for example, melting of the Greenland ice sheet), ocean-atmosphere (change in water temperature), and biosphere (death of coral reefs), according to a report by the European Space Agency (ESA).

 

All data by ERA5

11. As per the latest UNEP report, above 1.5°C, risks and impacts will intensify with every extra fraction of a degree and every year. 

12. Anticipated impacts include intensified extreme weather, ecosystem loss, and submersion of Small Island Developing States and low-lying coastal cities.  Severe damage to human health, food security, water supplies, nature, cities, infrastructure, and economies is expected.

Has the limit been breached before? 

1. The 1,5 degree Celsius threshold for annual averages has already been breached once, in 2024, the warmest year ever recorded, in which the average temperature happened to be 1.55 degree Celsius above pre-industrial times. 

2. Monthly averages have topped the 1.5 degree limit several times, particularly between July 2023 and December 2024. 

3. However, when scientists talk about 1.5 or 2 degree Celsius temperature thresholds, they refer to long-term temperature trends, and not individual year aberrations that can be caused by some abnormal event. 

4. The record temperature in 2024, for example, was significantly influenced by the El Nino event. The following year, 2025, the warming came down to 1.45 degree Celsius.

5. The UNEP report, however, warns that the world is now entering an era where annual average temperatures would be consistently higher than 1.5 degree Celsius.

What does the report recommend for mitigation?

6. The report lays out a three-step response to overshoot. In the immediate future, countries need to slash emissions and protect vulnerable people and ecosystems. 

7. At peak warming, the world would need to reach at least net zero while coping with severe impacts. After that, bringing temperatures down would require sustained net-negative CO₂ emissions, or removing more carbon dioxide from the atmosphere than is emitted.

8. The report stresses that mitigation and adaptation have to happen together. Weak emissions cuts can make adaptation harder and more expensive, while poor adaptation can leave people and infrastructure exposed to climate risks.

BEYOND THE NUGGET: India’s updated climate targets

1. India on March 25, 2026 revealed its climate targets for 2035, promising to make further progress on cutting the carbon intensity of its economy, expanding the deployment of renewable energy and creating carbon sinks from forests and trees.

2. India said it would ensure that at least 60% of its electricity installed capacity in 2035 was based on non-fossil fuel sources, up from the 50% target it had set for 2030. 

3. It has promised to attain at least a 47% reduction in emissions intensity, or emissions per unit of GDP, on 2005 levels, which is two percentage points more than its current target of 45% for 2030. 

India’s NDCs on climate

4. And, it has promised to create a carbon sink that is at least 3.5 to 4 billion tonnes of CO2-equivalent larger than what existed in 2005.

5. Each of the new targets marks a progression over existing commitments for 2030, a mandatory requirement under the 2015 Paris Agreement. Under this 2015 pact, every country is obligated to decide upon, and implement, a set of climate actions that help the global fight against climate change. 

6. These are referred to as nationally-determined contributions, or NDCs— emphasising the fact that countries themselves decide the nature and scale of climate actions.

Post Read Questions

(1) Consider the following statements: (UPSC CSE, 2025)

1. Carbon dioxide (CO₂) emissions in India are less than 0.5 t CO₂ / capita.

2. In terms of CO₂ emissions from fuel combustion, India ranks second in Asia-Pacific region.

3. Electricity and heat producers are the largest sources of CO₂ emissions in India.

Which of the statements given above is/are correct?

(a) 1 and 3 only

(b) 2 only

(c) 2 and 3 only

(d) 1, 2 and 3

(2) With reference to India’s Nationally Determined Contributions (NDCs) under the Paris Agreement, consider the following statements:

1. Increasing the share of non-fossil fuel-based (excluding nuclear and large hydropower) installed electricity capacity to 60% by 2035 is one of the targets under NDCs.

2. India’s target of reducing the emissions intensity of its GDP by 47% by 2035 is to be measured with reference to the 2005 level.

3. NDCs are legally binding under the Paris Agreement, and failure to achieve their targets attracts international legal sanctions.

Which of the statement/s given above is/are correct?

(a) 1 and 2 only

(b) 2 only

(c) 2 and 3 only

(d) 1, 2 and 3 only

Answer key: 1. (c) 2. (b) 

(Sources: 1.5 degree Celsius breach inevitable now, says new UNEP report, Highway to ‘climate hell’: What breaching the 1.5 degree Celsius warming threshold could mean, UNEP says 1.5°C warming overshoot is now ‘unavoidable’. What does it mean for climate action?, Understanding the impacts of climate change and the path to effective adaptation, India’s new climate targets are modest, but significant. Here’s why)

🚨 Click Here to read the UPSC Essentials magazine for August 2026. Share your views and suggestions in the comment box or at manas.srivastava@indianexpress.com🚨 

Subscribe to our UPSC newsletter. Stay updated with the latest UPSC articles by joining our Telegram channel – Indian Express UPSC Hub, and follow us on Instagram and X