The heat is on! Fifth IPCC report explained

By Bronte Hogarth

The Intergovernmental Panel on Climate Change (IPCC) has released its Fifth Assessment Report and the results are clear. The heat is on! and the time for action on climate change is now.

The IPCC was established in 1988 to review and report on published climate science. Every six years or so it releases its report on the current scientific understanding of human induced climate change. The Fifth IPCC Assessment or AR5 was released on September 27th and has a strong degree of certainty that human activities are responsible for global warming over the past half-century, now “extremely likely” as opposed to “very likely” as published in the 2007 IPCC report.

It says there is now a 95 percent probability that humans are responsible for global warming, a big leap from 2001 where a 66 percent certainty was stated.

It also expresses the impacts of that warming on the Earth in the form of melting ice, rising sea levels and extreme weather activities.


There are more than 830 experts from 85 countries who contributed to the IPCC’s Fifth Assessment Report. They represent a diverse range of fields, including oceanography, economics, physics, meteorology and social sciences and the report has a greater emphasis on assessing the socio-economic aspects of climate change and its implications for sustainable development.

The report goes through many different models and projections for the coming years regarding continued ocean and atmospheric warming, and reductions in snow and ice resulting in global sea level rises. Here are some conclusions:

  • Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850.
  • The majority of the modelling points to a global mean sea-level rise of between 26 and 82 centimetres by 2100. The worst case scenario is for a sea level rise of 98cm.
  • The majority of climate models point to a mean temperature rise of around 2 degrees Celsius. The smallest predicted temperature rise is 0.3C and the largest rise is 4.8C.

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A pertinent part of the report, which has been left out of much recent reporting on the AR5 is that most aspects of climate change will persist for many centuries.

This represents a substantial multi-century climate change commitment created by past, present and future emissions of CO2.

We need global reductions in CO2 emissions right now, but this is now an inter-generational issue. Whether in the developed or developing world, climate action and mitigation strategies need to be constantly looking to the future, teaching and equipping the younger generations with the tools necessary to live better for the planet, and in the developed world to live a lifestyle of less. Less stuff, less waste, less non-renewable energies, less emissions!

The report is another piece of evidence in an already clear case for urgent action on climate change and a wake-up call for all generations. We need to do it now, and we need to do it together.

Follow Bronte on Twitter @brontehogarth

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