2°C Too Hot For Ice & Rising Seas – A Conversation with ICCI Director Pearson

2°C Too Hot For Ice & Rising Seas – A Conversation with ICCI Director Pearson

By Pam Pearson 21 November, 2023

Lead ice scientists are calling to “take 2°C off the table” and you'll understand why from our conversation with ICCI Director Pearson, who makes it clear just how bad the situation is for our cryosphere, ice sheets & sea level rise but she still has some hope

On 22 September 2023, the Ambition on Melting Ice (AMI) and International Cryosphere Climate Initiative (ICCI) hosted “The Road to COP28: Melting Ice, Rising Seas and Why 2°C is Too High”. Together they urged the UN New York Climate Ambition Summit to “take 2°C off the table” to prevent catastrophic impacts from melting ice and sea level rise (SLR). The event highlighted the escalating climate impacts and the pressing cryosphere tipping points – all of which will have devastating impacts for all of us. The presentations delivered left us deeply concerned and we reached out to Pam Pearson, the director of the AMI Secretariat and ICCI to gain more insights on this urgent matter.

CWR: For those of us based in Southeast Asia, we rarely see ice and snow. So changes in the cryosphere are hard to imagine as they are out of sight and out of mind. But they are clearly important. Could you share with us how these changes can impact us and what your biggest fears are?

Pam Pearson (PP): Cryosphere scientists often say that what happens in the cryosphere does not stay in the cryosphere: it impacts the entire planet! Nowhere is this perhaps more true, than for Southeast Asia; where much seasonal water comes from glaciers and snow in the Hindu Kush Himalaya, very much threatened by global warming.

The cryosphere impacts the entire planet…

…but is especially more true for SouthEast Asia region

But from even farther away, the Earth great ice sheets – Greenland and Antarctica – can threaten many coastal cities in this region, because they are so low-lying. So protecting the cryosphere by slowing global warming is a matter of concern for the region of Southeast Asia, perhaps even more so than for those living in the regions where the ice is melting.

CWR: Indeed, many Asian capitals are coastal, and sea level rise will clearly be a concern. In your latest AMI-ICCI event you said that “2°C is too high” for melting ice and rising seas. Can you explain why previously we thought 2°C was ok but now we must stay within 1.5°C? Is it because observed impacts in the cryosphere are worse than we thought?

(PP): Yes, based on what we have seen in the past 20 years, loss from both ice sheets is running well ahead of earlier projections. Many ice sheet scientists never thought they would see this level of melt in their lifetimes. There has also been a great deal of work done by paleo-climatologists over this period showing that in Earth’s past, when temperatures were 2°C over pre-industrial, sea levels were 12-20 meters above today; and even at 1.5°C, 6-9 meters higher.

Ice sheets loss is running well ahead of earlier projections…

…1.5°C is in the danger zone; 2°C is definitely too high

The only question is how long we would need to stay at those temperatures to trigger such dangerous levels of sea-level rise; but work on projections since the Paris Agreement was signed in 2015 show it might be a matter only of decades. So even 1.5°C is in the danger zone; 2°C is definitely “too high.”

CWR: Is this why “low likelihood high impact” events such as multimeter sea level rise are now included in the IPCC’s Summary for Policymakers? Interestingly, the IPCC warns that 2m of sea level rise (SLR) by 2100 and 5m by 2150 “cannot be ruled out due to deep uncertainty in ice sheet processes” but some renowned ice scientists like the late Konrad Steffen has said that 5m could happen possibly in the next 50-100 years.

This sounds unimaginable – could we really be heading for 5m of SLR? What’s accelerating the melt (permafrost thaw/albedo effect/ocean warming/ marine ice sheet instability (MISI)/ marine ice cliff instability (MICI))?

(PP): If we continue our current use of fossil fuels, which is responsible for about 80% of carbon dioxide emissions; we could well be headed towards such extreme levels. Ice sheets might be able to collapse much faster than we thought: again drawing from Earth’s past, there have been periods when sea levels rose between 3-4 meters per century (the last time, about 14,500 years ago was probably due to collapse of the Laurentide ice sheet over Canada).

Continuing current use of fossil fuels could result in such extreme levels…

…CO2 concentrations today much higher at 424ppm vs 180ppm during ice ages = world is warming much faster

But the really serious issue is that those past rapid increases in sea levels were taking place in a world that was not warming nearly as fast as ours today. Some of the dynamics mentioned – MISI, MICI, and especially warmer ocean waters on the edges of ice sheets – likely played a role in the past, and will in the future if warming continues. But the main thing accelerating the melt is simply the rise in CO2 and therefore, global temperatures.

People forget that even in what were called “warm” periods in past periods of ice sheet melt, CO2 levels were around 280ppm; and they were then down at 180ppm during ice ages. So today’s CO2 concentrations, at 424ppm really are unprecedented in at least 3 million years. Of course the world is warming drastically as a result – it can’t help but react to our fossil fuel emissions.

CWR: Even without accounting for permafrost emissions, it looks like we will overshoot the 1.5°C Paris target sooner rather than later. Already, this September was 1.75°C warmer than pre-industrial levels putting us on track for 1.4°C of warming for 2023. Can we overshoot 1.5°C and dial back emissions later this century? Will this reverse/slow down cryosphere changes including sea level rise? Or is melting ice locked-in and rising seas irreversible?

(PP): It depends very much on what is meant by “later this century.” We really need to dial back emissions this decade, before 2030. If we do not, then bringing down CO2 levels and temperatures close to 1.5°C becomes impossible; and for each tenth of a degree we go higher, the changes become more and more irreversible. So this truly has become an emergency situation, because CO2 levels just keep on rising equally fast each year, and the world keeps warming as a result.

“Thinking we can turn back the clock in 2040 or 2050 or 2060 without causing extensive global loss and damage is a fantasy…”

Thinking we can turn back the clock in 2040 or 2050 or 2060 without causing extensive global loss and damage is a fantasy; and we need to face physical reality. This is where the phrase, “We cannot negotiate with the melting point of ice” arose.

CWR: If we can’t “negotiate with ice” we must surely negotiate new policies to address permafrost emissions, melting ice, sea level rise and so on. Also, should more local research with regards to SLR impacts be carried out to inform “transformative” and “low-regret” adaptation planning? With COP28 around the corner and Asia being the most vulnerable region to rising seas … what are your top recommendations for policymakers?

(PP): The absolute top priority is to address the cause: fossil fuel emissions. I understand that is terribly hard – I’m actually from Texas, and was born in the midst of the oil boom there – but we really have to face up to the harsh reality of what these resources have cost us, and will cost future generations. These were tremendously transformative fuels, but their time is well past, and further development needs to use other, non-carbon emitting sources alone.

Absolute top priority is to address the cause: fossil fuel emissions…

…we need a course correction to take 1.5°C much more seriously; it’s still possible to do this transformation in time…

This is where negotiations such as those at COP28, fittingly actually in Dubai, come in and are so important: we need a course correction to take 1.5°C much more seriously, with actual efforts to make that our peak temperature. Many experts have outlined how to get there; we just are not making the needing changes quickly enough to make the 1.5°C mark.

It’s still possible to do this transformation in time; and then the costs of adaptation will be far, far lower. For example, higher sea levels – while they may still be inevitable – will rise much more slowly, in centuries rather than decades. It’s really, really hard to plan reliable local adaptation measures until we know the rate and pace of changes that we’ll be facing – otherwise, we may focus on the wrong measures entirely. That’s a huge challenge to adaptation experts today.

…also need to adapt & prepare to carry those burdens

So: address the root cause (mitigation); prepare for what we can no longer prevent (adaptation); and through those two steps, try to hold down the catastrophic current and future impacts (loss and damage). But we need to prepare to carry those burdens as well, because those worst impacts largely hit the most vulnerable the hardest, with the least resources today.

Further readings

• Too Fast, Too Soon – Vanishing Ice & Rising Seas – With persistent global warming, the ‘Big Melt’ we fear has begun in the polar regions, leading to unprecedented ice loss & devastating sea level rise. Get on top of some ice cold facts with CWR’s Tan & Low
• Futureproofing APAC Banks & Savings — Find out which 17 major APAC banks are on track of sinking loan books totaling US$7.9trn
• Hong Kong Rising Seas Adaptation Is Way Behind New York & Singapore — Wrong adaptation levels could sink HK’s future. CWR’s Low & Tan highlight key planning stumbling blocks & layout steps HK urgently needs to take

More on Latest

• What Does 1.5°C Mean For Water? A Conversation with WMO Director of Hydrology, Water & Cryosphere Dr. Uhlenbrook – To unpack what unprecedented temperatures means for extreme events, melting ice & sea level rise, we chat to Dr. Uhlenbrook, WMO Director of Hydrology, Water & Cryosphere. Plus, see how soon he thinks we will cross the 1.5°C threshold
• The Ocean & Climate Platform Launches Its Recommendations For Coastal Cities To Adapt To Sea Level Rise – Adapting to irreversible rising seas is a collective challenge so to help cities, OCP released policy recommendations. Bongarts-Lebbe shares key priority areas & what’s next