The present and future of climate change: A Himalaya without ice and snow heralds a future Hothouse Earth

It’s been a couple of months since I last wrote this column, choosing to get away from dire climate news for a hike in Sikkim. But even there, surrounded by incredible natural beauty, with the imposing Kangchenjunga massif on the horizon, it was easy to see the rapid changes that climate change is making to local ecologies, and communities.

In the middle hills of west Sikkim, one complaint that echoed was that local water sources, like perennial springs, are drying up. Towards a large urban centre like Darjeeling, overlooking the Rangit river valley, this problem is more acute, but even for sparsely populated villages like Rinchenpong, a few ridges to the north, this is a growing worry.

Meanwhile one just needed to look northwards towards the world’s third highest mountain to witness a stark reminder of the climate crisis—the lack of snow and ice in the Himalaya. The highest mountains were certainly snowclad, but it is clear that the snowline—that is the altitude till which precipitation occurs as snow—is receding, and former snowy ridges are just bare rocks…and that too at the end of December!

This is primarily because winter snowfall is increasingly late. Where the first snowfall of the season used to be in December, of late this doesn’t occur till mid-to-late January. At the other end of the seasonal spectrum, winter is giving way to a shorter spring and then summer earlier than ever, while the severity of the summer months is increasing. A local tour guide, Binodh Gurung, says that this is being felt in the trekking season as well. “It is getting increasingly difficult to predict what the weather will be like in any season,” he says, adding that this is very different from more settled climate patterns that have been the norm.

His assertion is borne out by climate data. According to a report published in November on the effects of climate change on India, prepared by Indian climate scientists, between 2015-2024, the average air temperature was 0.89 degrees Celsius hotter than the baseline of 1901-1930. Between 1951-2024, the number of warm days in northeast India has increased by 10-15 days per decade. As the overall air temperature increases over the Indian subcontinent, the temperature increase is greater in the Himalaya. Between 1951-2020, the mean average temperature over the Himalaya rose at the rate of 0.28 degrees Celsius per decade, while at elevations of over 4,000m—which is usually the snowline—the rate of heating has been higher, at 0.34 degrees Celsius per decade.

Even at low levels of fresh planet-heating carbon emissions, by the end of the century, the Himalaya will heat up by 2.5 degrees Celsius over pre-Industrial times. If the planet heats up by 1.5-2 degrees Celsius by 2100 (we’re currently at about 1.4 degrees Celsius of warming), Himalayan glaciers will lose up to 50% of their volume. At current levels of warming, Himalayan glaciers would dwindle by 80%. This has grave implications for mountain communities, especially in a state like Sikkim, because the eastern Himalaya is projected to be especially badly affected by global warming.

While it is easier to see the effects of climate change in the Himalaya, the situation is dire everywhere, with the world quite close to hitting vital climate ‘tipping points’. These can be understood as points of no return for vital planetary systems, like the Himalaya, coral reefs, the Greenland ice sheet or the Amazon rainforest. Once rising heat destabilizes these systems, no matter what we do to control climate change, parts of the world will become infinitely more dangerous. One of these, the collapse of coral reefs around the world, has already begun, according to the Global Tipping Points Report, which was released late last year.

A study released last week, titled The Risk of a Hothouse Earth Trajectory, states the fast-changing planet in stark terms. “Earth’s climate us now departing from the stable conditions that supported human civilization for millennia…uncertain tipping thresholds make precaution essential, as crossing them could commit the planet to a hothouse trajectory with long-lasting and potentially irreversible consequences.” What is “Hothouse Earth”? The title comes from a renowned book from 2022 by volcanologist and climate-hazard specialist Bill McGuire. It paints the vivid picture of a not-so-distant era when multiple earth systems are destabilized enough that this creates a feedback loop of rapid, continuous warming to levels that have not been seen for hundreds of thousands of years. And once this cycle of tipping points and feedback loops are reached, then the climate crisis slips out of our control, and the planet becomes uninhabitable for human beings.

The report states that we are closer than ever to reaching this point, and that governments have to act with a renewed sense of urgency to ditch fossil fuel use. Speaking to The Guardian, one of the co-writers of the report, scientist Christopher Wolf said that the truly alarming thing is that policymakers and the public remain largely unaware of the risks. “It is likely that global temperatures are as warm as, or warmer than, at any point in the last 125,000 years.” Climate change, as Dr Wolf asserted, “is advancing faster than many scientists predicted.”