By John Kerr 23/05/2017 1


Children alive today will find themselves living in a totally different climate in the future, should greenhouse gas emissions continue unchecked, warns a new study.

Climate change does what it says on the tin – it changes the climate. The question of when and where we will start to notice those changes is tackled in a new, Kiwi-led study published today in Nature Climate Change.

‘Unfamiliar’ climates

From year to year there is a lot of variability in the local climate, some years are warmer than average, some cooler. The new research aims to separate the future climate change ‘signal’ from the ‘noise’ of this normal variation, with a focus on the human dimension. At which point does a future local climate become so unusual that an individual would see it as significantly different from, say, when they were a child?

The researchers outline some key definitions for talking about the range of annual temperatures now and in the future under different emissions scenarios. They identify a new climate as ‘unfamiliar’ if a year that is now normal would only have occurred once in an individual’s lifetime, or as ‘unknown’ if it would have occurred once every few hundred years or more, on average.

Change on the horizon

Our current, business-as-usual approach to emissions would see unfamiliar climates emerging around the world within decades, the researchers warn.

“Overall, we found new climates emerge faster in inhabited areas, especially in the tropics, than in the world as a whole,” explains lead author Professor Dave Frame from Victoria University of Wellington in media release.

“People living in tropical regions, such as the South East Asian nations and the Pacific Islands, are almost certain to experience ‘unfamiliar’ or even ‘unknown’ climates by the end of this century if climate change is not slowed down. The situation is almost as stark for many tropical African countries too.”

Read more about the research on Scimex.org.

Slowing emissions slows change

unfamiliar climates
How different will the end of the century be compared to now? These maps compare a future where emissions peaked between 2010-2020 (top) and one where emissions continue to rise throughout the 21st century (bottom). Darker colours indicate a greater departure from current climate variability* (Frame et al., 2017, Nature Climate Change).

“Many people alive today could reap the benefits of slowing or stopping climate change,” says co-author Dr Manoj Joshi of the University of East Anglia.

“Projections of twenty-first century climate made with significantly reduced carbon emissions show that tropical climates, especially those areas with very high populations, can avoid such emergence, staying far more ‘familiar’ to the people who live there.”

“Some amount of warming is inevitable,” adds co-author Dr Ed Hawkins from the University of Reading. “However, keeping climate within some bounds of familiarity mean that people can adapt more easily to whatever change does arrive.”

In our lifetimes

The new study addresses an issue critical to the development of plans reduce greenhouse gas emissions. One of the challenges of creating effective climate change mitigation policies is the dealing with the mistaken belief that future benefits are beyond the lifetime of people alive today. For example, on the difficulty of lowering emissions, Georgetown University Professor of Law Richard Lazarus writes:

The time lag is at the very least longer than the lifetime of any adult. The upshot is that no one who is asked to curtail activities to reduce greenhouse gas concentrations will be likely to live long enough to enjoy the benefits of that curtailment.

The new Nature Climate Change paper puts that fallacy to bed:

Our analysis shows that near-term mitigation initiatives can prevent many climates from becoming radically different from those experienced in the recent past, that such effects happen well within a human lifetime, and that this is especially true for those whose communities would otherwise change fastest.

In other words, many of the longterm benefits of mitigation can be internalized by many people alive today

 


Featured image: Public Domain.

*This figure from the paper (Fig 3b & 3e) compares the 50th percentiles of two IPCC greenhouse gas concentration scenarios, RCP2.6 and RCP8.5, displaying the ratio of climate signal to noise (S/N)—a measure of the amplitude of change expressed in terms of units of existing variability.

 


One Response to “Avoiding the strange of climate change”

  • Once again, it seems to be all about emissions with little or no mention of tropical deforestation (plants=CO2 -> O2). It is interesting that they claim that climate change is greatest in the tropics (I wonder why!) Also, they talk about separating “signal” from “noise”, but what about separating natural “signal” from anthropogenic “signal”?

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