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Climate change

Climate Science - Part 3

We know that extreme weather events will increase in severity and frequency as our climate continues to warm. Exactly how much, well, that depends on our choices.

River delta from space

Climate Change - Yes It's Bad!

We’ve all experienced extreme weather. It can disrupt holidays, festivals, sports fixtures, as well as work or school, and daily life in general.  

If you stop to think about it, has the number of times you’ve been prevented from doing something you wanted, needed or had planned to do increased in recent years due to extreme weather? 

According to climate scientists, this will happen more and more, as the planet struggles with the impacts of climate change. 

Excessive temperatures 

In Europe, excessively high or low temperatures presently cause 407,0001 fatalities a year, according to the EU. In the future, it’s predicted that heat-related deaths, currently six times more frequent in southern than in northern Europe, will occur 9.3 times more frequently in the south than in the north by 2100. 

Flooding 

According to data based on satellite imagery published in the journal Nature, the global population at risk from flooding has risen by almost a quarter since the year 2000, far greater than previously predicted by computer models. This is due to migration and increasing climate-change related flood events. Flooding is the environmental disaster that impacts more people than any other.  

Wildfires 

Across the globe we’re also seeing an increasing frequency and intensity of extreme wildfires, with the number and intensity of the most extreme wildfires revealed to have doubled over the past two decades. It feels like the planet is literally burning around us. As I write, more than 14 wildfires are raging in California, fueled by erratic winds and temperatures of over 100C. Recently more than 70 wildfires burned simultaneously in Greece. And after the warmest August on record, Australia is bracing itself for its worst ever wildfire season.  

Sea temperatures and ice melt 

Analysis published by the BBC4 in May revealed the world's oceans broke temperature records every single day over the past year. Nearly 50 days broke existing record highs for the time of year by the largest margin in the satellite era.  

The BBC report says greenhouse gasses are predominantly to blame, with the recent El Nino also helping to warm the oceans, impacting negatively on coral and other marine ecosystems. 

Biodiversity loss 

It’s not just humankind suffering the impacts of climate change. The Living Planet report published by WWF in 2022 revealed an average 69 percent decline in global wildlife populations since 1970. The WWF director said: 'The planet is in the midst of a biodiversity and climate crisis… and we have a last chance to act… A nature-positive future needs transformative - game changing - shifts in how we produce, how we consume, how we govern, and what we finance.'

Tipping points 

You might have heard about climate tipping points and been wondering what they are. Essentially there are seven-to-nine elements of the planet’s stability that are currently hanging in the balance.  

These are: 

  1. (a) Irreversible retreat of the Greenland ice sheet caused by rising temperatures and leading to a potential rise in sea levels of as much as seven metres; (b) at the South Pole, the West Antarctic ice sheet also risks collapse leading to potential sea level rises 

  1. Loss of the Arctic permafrost and thawing of frozen soils rich in carbon leading to a double whammy sudden increase in CO2 and methane emissions 

  1. Shifting biomes, meaning boreal forests expand into (grassy?) tundra in the north and forests dieback in the south 

  1. Due to ongoing deforestation and hotter, drier conditions, the Amazon rainforest is at risk of dieback and changing from a rainforest into a savannah, causing a vicious cycle of further decreased rainfall and biodiversity loss 

  1. The West African monsoon could shift either northwards due to wetter conditions or southwards if drier, leading to wider ecosystem change and disruption to agriculture causing food insecurity or famine 

  1. Likewise rising CO2 emissions could cause the Indian monsoon to strengthen or rising methane emissions could cause it to weaken, leading to greater extremes in rainfall and again disruption to agriculture 

  1. An end to the coral reef? Rising temperatures risk pushing warm water corals beyond tolerable levels of thermal stress, shifting them into an alternative state dominated by macroalgae, ultimately causing a significant change in the ocean ecosystem as well as losses for tourism and fisheries. 

  1. Lastly, there’s an important Atlantic ocean circulatory stream (like the jet stream?) called the Atlantic Meridional Overturning Circulation – this faces disruption or even shutdown as a result of increased freshwater into the North Atlantic, meaning significantly cooler temperatures in some areas 

So where do we go from here? 

Positive tipping points to the rescue 

‘To avoid what I call the climate tipping points that are a source of existential risk to me, my kids, your kids, your grandkids, and all the generations to come… it's absolutely clear to me as a climate scientist that we have to stop fossil fuel burning as soon as we can and limit what I call the cumulative emissions of greenhouse gases,' says Professor Tim Lenton, Professor of Climate Change and Earth System Science at the University of Exeter.

‘It's also absolutely clear that we're going nowhere near fast enough at doing that. We need to go at least five times faster in decarbonising the economy, and the only credible way to do that now is through self-perpetuating exponential change, what I'm calling positive tipping points.’ 

Lenton’s ‘positive tipping points’ are major changes in society, such as the shift to electric cars or renewable energy, that tip the balance towards exponential decarbonsation; like TikTok’s latest - societal and economic changes that gain momentum and quickly become the norm.  

Lenton recognises that climate doom can be disempowering, paralysing and confusing, but says, ‘we can all be part of accelerating the change.’ 

'The crucial idea behind the tipping point is that when amplifying feedback within a system gets so strong, it just keeps propelling change without you having to push the system anymore.'

For example, in 2012, 40 percent of the electricity used was generated by burning coal, whereas by 2020 that  had shrunk to just 1-2 percent. But, Lenton, adds, Nobody noticed because they don't think about where the electricity comes from when they switch the light on.’ 

Lenton’s optimism is reflected in that of data scientist Hannah Ritchie, author of ‘It’s not the end of the world, who shows us ‘how to be the first generation to build a sustainable planet’ saying, 'If we take several steps back, we can see something truly radical, game-changing and life-giving: humanity is in a truly unique position to build a sustainable world.'

Professor of Earth Sciences and Zero adviser, Professor Caroline Lear concludes: 'Decades of research, summarised by the IPCC, shows that, far from just another hurricane, forest fire, exceptional flood or extra hot day, the current events impacting on the interconnected climate system are, as they say in the report, “unprecedented over many centuries to many thousands of years”. We know these events will increase in severity and frequency as our climate continues to warm. Exactly how much, well, that depends on our choices.’ 

Let’s get started.