According to their study published in Science today, reducing the magnitude of climate change is also a good investment. Over the next few decades, acting to reduce climate change is expected to cost much less than the damage otherwise inflicted by climate change on people, infrastructure and ecosystems.
“Acting on climate change” said lead author Prof Ove Hoegh-Guldberg, from the ARC Centre for Excellence in Coral Reef Studies at the University of Queensland in Australia, “has a good return on investment when one considers the damages avoided by acting.”
The investment is even more compelling given the wealth of evidence that the impacts of climate change are happening faster and more extensively than projected, even just a few years ago. This makes the case for rapidly reducing greenhouse gas emissions even more compelling and urgent.
Prof Hoegh-Guldberg explained the mismatch: “First, we have underestimated the sensitivity of natural and human systems to climate change, and the speed at which these changes are happening. Second, we have underappreciated the synergistic nature of climate threats – with the outcomes tending to be worse than the sum of the parts. This is resulting is rapid and comprehensive climate impacts, with growing damage to people, ecosystems, and livelihoods.”
For example, sea-level rise can lead to higher water levels during storm events. This can create more damage. For deprived areas, this may exacerbate poverty creating further disadvantage. Each risk may be small on its own, but a small change in a number of risks can lead to large impacts.
Prof Daniela Jacob, co-author and Director of Climate Services Centre (GERICS) in Germany is concerned about these rapid changes – especially about unprecedented weather extremes.
“We are already in new territory,” said Prof Jacob. “The ‘novelty’ of the weather is making our ability to forecast and respond to weather-related phenomena very difficult.”
These changes are having major consequences. The paper updates a database of climate-related changes and finds that there are significant benefits from avoiding 2oC and aiming to restrict the increase to 1.5oC above pre-industrial global temperatures. MORE