As Super Typhoon Bavi churns towards Taiwan and eastern mainland China, they offer a chilling timely reminder that the world needs to brace for impending disasters as the climate system nears a tipping point.
For Benjamin Horton, the newly minted recipient of the Asia Oceania Geosciences Society Axford Medal – the most prestigious honour in Asian climate and earth science – the world has entered a period of volatility in which historical weather patterns are no longer a reliable guide to future risk.
“Look at what is happening to the planet. It is spiralling out of control. Climate is accelerating far faster than we thought it would,” said Horton, dean of the school of energy and environment at City University of Hong Kong.
“The Earth is incredibly sensitive,” he added. “It has a planetary boundary, and we are right at the edge of it. That means that the system is prone to extremes, which we find very hard to predict exactly where and when.”
The concept of planetary boundaries defines the environmental limits within which humanity can safely operate. According to the Stockholm Resilience Centre, humanity has already crossed seven of these nine critical limits, including those relating to climate change, land use and fresh water.
Typhoons like Bavi that undergo rapid intensification pose severe forecasting challenges. Within just a day or two, a relatively modest threat can escalate into a major hazard as maximum sustained winds surge abruptly, often fuelled by exceptionally warm ocean waters and favourable atmospheric conditions.
Horton said there was “growing scientific evidence that the most intense tropical cyclones are becoming more likely to undergo rapid intensification as ocean temperatures rise”.
“While we cannot attribute any single storm solely to climate change, a warmer ocean provides more energy for storms to tap into.”
Horton warned that climate change had ushered in a new precarious baseline in which “you do not need to have a really bad typhoon season”.
“You just need an average typhoon season plus climate change, and every time it then becomes something we have never seen before.”
He said climate change had “completely undermined” the assumption that the climate was relatively stable, rendering statistics derived from historical observations increasingly obsolete.
Consider the term a “once-in-500-years” event: historically, this implies a 0.2 per cent probability of occurrence in any given year.
“As the atmosphere warms and holds more moisture, and as sea-surface temperatures rise, some extreme events are becoming more likely and more intense,” Horton said.
“In other words, what was considered a ‘500-year’ event based on the past climate may become substantially more frequent in the future climate.”
His team’s research on 2012’s Hurricane Sandy, which caused nearly 150 deaths across the Atlantic basin and over US$60 billion in damage in the United States, illustrated this shift.
Without climate change, it was a “once-in-500-year” rarity. Now it is a “50-year” event, and by 2050, it is projected to recur every five years.
“The bigger issue is that we are estimating rare-event probabilities in a climate that is changing,” Horton said.
“The historical record may no longer be a reliable guide to future risk. That means return periods should increasingly be viewed as moving targets rather than fixed numbers.”
Similar challenges arise in forecasting extreme heat.
“You do not need to have the worst heatwave in Europe. All you need is an average heatwave plus climate change,” said Horton, who pointed to last month’s heatwaves as “worrying”.
“The weather does not really get to its maximum heat until August, so what is going to happen then?”
Horton said the climate system could not absorb repeated intensified heatwaves, saying that every time one occurred, “it dries out the soil, which means next time it occurs, it gets even hotter”.
“The system is going to break.”
According to Horton, the danger lies in the breakdown of social and energy systems when climate hazards recur with relentless frequency and evolve from weather events into “humanitarian disasters”.
In the recent heatwaves in Europe and the United States, energy grids and water management struggled to cope.
Due to extreme heat, Fourth of July celebrations were cancelled in several parts of the US, including a parade in Philadelphia, where the Declaration of Independence was signed 250 years ago.
Horton contrasted the amount of carbon in the atmosphere 250 years ago, which he said was about 280 parts per million by volume, with today’s reading of 425ppm.
“Temperatures were 1.5 to 1.6 degrees Celsius cooler than today. They did not have record-breaking heat, wildfires and storms. They do now.”
“Are people coming to terms that this is now the new reality? Or are they still thinking it will go back to what it was? It will not,” he said, voicing worry about whether happiness and good health could be attainable amid “such incredible destruction”.
Of the warming El Nino phenomenon, he said the temperatures in the Pacific Ocean now indicated “an event of the magnitude of the biggest El Nino in 1997-98 or 1982-83, but plus climate change, so it will be worse”.
Horton argued the world was headed into “uncharted territory”, saying “we will really suffer as a result because our system is strained”.
As for earthquakes, while they were irregular, societies needed substantial social capital to recover from natural disasters, he said, adding that climate change “can break communities and then you lose it because people become migrants”.
Yet, Horton dismissed the doomsday view that civilisation was on the precipice of collapse.
He cited a growing arsenal of underutilised solutions, from the global transition to renewable energy, advanced solar cell efficiency and ultra-white cooling paints for buildings to nature-based strategies such as restoring ecosystems.
“Nature responds really quickly,” he said, referring to the natural world’s recovery during the coronavirus pandemic. “We give life an opportunity, it takes it.”
Horton also said the undergraduate students he interviewed during recent university admission drives offered a reason to be optimistic.
“The students want to come because they see our school as looking at the problems and finding the solutions. That gives you hope because they all want to ... save the planet.”
Horton’s message for the next decade is one of urgency, not defeat.
He sees a future in which a social icon could serve as a catalyst for global influence, transforming environmental stewardship into a fashionable movement that helps people raise their standard of living.
“It is not going to be easy. It takes a lot of effort. But it is very solvable.” -- SOUTH CHINA MORNING POST
