An internationally respected group of scientists is calling on world leaders to urgently accelerate efforts to tackle climate change.
Almost every aspect of the environment and ecology is changing in response to global warming. Some of these changes will be profound, if not catastrophic, in the future.
According to a new study published in Science today reducing the magnitude of climate change is good investment. Acting over the next few decades to reduce the rate of change is expected to cost much less than the damage otherwise inflicted--on people, infrastructure and ecosystems--by not taking action.
"Acting on climate change has a good return on investment when one considers the damage avoided," said lead author Prof Ove Hoegh-Guldberg, Deputy Director of the ARC Centre for Excellence for Coral Reef Studies (Coral CoE) at the University of Queensland (UQ).
Climate change impacts are now occuring faster and are more extensive than previously projected. This makes the case for rapidly reducing greenhouse gas emissions even more compelling and urgent.
Prof Hoegh-Guldberg explained the mismatch. "First, we underestimated the sensitivity of natural and human systems to climate change and the speed at which these changes are happening," he said.
"Second, we underappreciated the synergistic nature of climate threats with the outcomes tending to be worse than the sum of the parts. This results in 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 and exacerbate the resulting damage. In already deprived areas this may intensify 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 Hoegh-Guldberg said.
Prof Daniela Jacob, co-author and Director of Climate Services Centre (GERICS) in Germany is concerned about these rapid changes--especially in regards to unprecedented weather extremes.
"We are already in new territory," Prof Jacob said.
"The 'novelty' of the weather is making our ability to forecast and respond to weather-related phenomena very difficult."
Such rapid changes are already having major consequences. The study points to significant benefits in avoiding global warming of 2oC and aiming to restrict the increase to 1.5oC above pre-industrial temperatures.
Prof Rachel Warren from the Tyndall Centre in the UK assessed projections of risk for forests, biodiversity, food, crops and other critical systems.
"The scientific community has quantified these risks in order to inform policy makers about the benefits of avoiding them," Prof Warren said.
Since the Paris Agreement came into force there has been a race to quantify the benefits of limiting warming to 1.5oC, so policy makers have the best possible information for developing the policy required to meet this target.
"If such policy is not implemented we will continue on the current upward trajectory of burning fossil fuels and continuing deforestation, which will expand the already large-scale degradation of ecosystems," Prof Warren said.
"To be honest, the overall picture is very grim unless we act."
A recent report from the United Nations projected that as many as a million species may be at risk of extinction over the coming decades and centuries. Climate change is not the only factor--but is one of the most important ones.
The urgency of responding to climate change is also front of mind for Prof Michael Taylor, co-author and Dean of Science at the University of the West Indies.
"This is not an academic issue--it is a matter of life or death for people everywhere," Prof Taylor said.
"People from small island States and low-lying countries are in the immediate cross-hairs of climate change," he said. "I am very concerned about the future for these people."
This urgency to act is further emphasised by the vulnerability of developing countries to climate change impacts as highlighted by Prof Francois Engelbrecht, co-author from the Global Change Institute of the University of the Witwatersrand in South Africa.
"The developing African countries are amongst those most affected in terms of projected impacts on economic growth in the absence of strong climate change mitigation," Prof Engelbrecht said.
Prof Hoegh-Guldberg reiterated the importance of the coming year (2020) in terms of climate action and the opportunity to strengthen emission reduction pledges in line with the Paris Agreement of 2015.
"Current emission reduction commitments are inadequate and risk throwing many nations into chaos and harm, with a particular vulnerability of poor peoples," Prof Hoegh-Guldberg said.
"To avoid this, we must accelerate action and tighten emission reduction targets so that they fall in line with the Paris Agreement," he said.
"This is much less expensive than suffering the impacts of 2oC or more of climate change."
"Tackling climate change is a tall order. However, there is no alternative from the perspective of human well-being and there is too much at stake not to act urgently on this issue."
'The human imperative of stabilizing global climate change at 1.5°C' is published today. DOI: https:/
Prof Ove Hoegh-Guldberg (currently in Washington DC, USA)
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