The IPCC Fifth Assessment Report is OUT!!

The Intergovernmental Panel on Climate Change (IPCC) has released its fifth assessment report on climate change.

You can read the full report here.

The report is very, very long. Even the systhesis report which is an overview of the knowledge comes in at 116 pages.

So what key points can we take away from it?

“Human influence on the climate system is clear, and recent anthropogenic emissions of greenhouse gases are the highest in history. Recent climate changes have had widespread impacts on human and natural systems.”

This is to say that YES climate change has been driven by human influence and human resource use and exploitation. There is no hiding from it (though some will hide) we are responsible for global climate change.

Anthropogenic Green House Gas Emissions since the 1970's. You can clearly see that they are increasing

Anthropogenic Greenhouse Gas Emissions since the 1970’s. You can clearly see that they are increasing and have risen more rapidly between 2000-2010 than in the previous three decades. (Graphic: IPCC).

What we know since the 1950’s is:

  • Snow and ice cover has been diminished.
  • Sea levels have risen.
  • The ocean and atmosphere are both warmer.

These are all at levels unprecedented over decades to millennia! This is not just normal fluctuations.

The Oceans have been the dominant warming environment. The largest increases have been in top 75 metres of the water column but increases have been measure at all depths including over 3000 metres (where estimates only began in 1992). In addition to this the ocean is also becoming more saline and far more acidic. In addition to the ocean warming there is also evidence that in coastal waters the oxygen concentration has decreased (warm water can hold less dissolved oxygen) as well which, is detrimental to coastal dependent species and reefs. If like me you are super interested int he ocean and the consequences for it you can browse the whole Ocean Observations Chapter.

Sea Levels have also risen in the period between 1901 and 2010. The mean rate of this sea level rise (very likely) was 1.7 [1.5 to 1.9] mm yr–1 between 1901 and 2010 and this increased to 3.2 [2.8 to 3.6] mm yr–1 between 1993 and 2010. Almost worldwide glaciers have been shrinking and the melting of sea ice has been contributing to the rise in sea levels.

What about the Atmosphere I hear you shouting…well in a very unsurprising turn of events it is also getting warmer.

“Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850.”

What are the causes of all this change:

“It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in greenhouse gas concentrations and other anthropogenic forcings together”

(a) Shows how the average yearly temperatures differ from the mid-century mean. (b) Shows how the surface temperature has increased since 1901.

(a) Shows how the average yearly temperatures differ from the mid-century mean. (b) Shows how the surface temperature has increased since 1901. (Graphic: IPCC)

Research from multiple studies have shown that it is extremely likely that human activities have caused more than half of the observed increase in Global Mean Surface Temperatures (GMST) from 1951 to 2010 and that more than half of the observed increase in GMST over this same period is very likely due to observed anthropogenic increase in greenhouse gas (GHG) concentrations. Also that, except for Antarctica, anthropogenic forces have made substantial contribution to surface temperature for every continental region in the mid-20th century.

To break it down a little:

  • Since 1950 anthropogenic affects have contributed to practically all temperature increases.
  • Natural forces have caused virtually none of the temperature rises (solar forcing has minimal effect on GMST).
  • All levels are above that which would have been expected with natural variability.

The biggest sources for CO2 emissions are, fossil fuel combustion, cement making and flaring in oil and gas production.

Where does this leave us all and how will it impact us?

Well extreme events are likely to occur more often and have been occurring more often since the 1950s. Such as less extreme cold days and nights; more extreme hot days and nights; more heatwaves and increases in extreme high sea levels. Also there are more land regions where the number of heavy precipitation events has increased versus where they has decreased.

So for the future the IPPC says this means:

“Continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems. Limiting climate change would require substantial and sustained reductions in greenhouse gas emissions which, together with adaptation, can limit climate change risks.”

The warming will lead to greater risks both new and old for natural and human systems. These risks will disproportionately impact poorer and disadvantaged people in all countries. If high emissions continue the impacts with be significantly negative for biodiversity, ecosystem services, and economic development and amplify risks for livelihoods and for food and human security.

What Must Be Done?

Well if temperature rises are kept below 2 °C above pre-industrial levels then we will be able to minimise human and natural impacts. This however will require a lot, a lot, a lot of input from governments and organisations for mitigation and adaptations.

Limiting warming to below 2°C or to 2.5 °C or 3 °C will all involve similar challenges, but over slower time periods. Limiting increased temperatures will require substantial emissions reductions over the next few decades, leading up to near zero emissions of CO2 and other Green House Gases by the end of this century. They will present challenges for technology, economics, institutions and society.

The only way for all of this to be successful will be for mitigation to be fast-tracked, governments to collaborate and industry to corroborate with imposed measures. It is possible that we can limit warming but only if globally we work as a single driven entity and not in our own self interest for economic advancement. This is because large economic of investments of billions of dollars a year into technology for carbon capture and energy efficiency.

This report is great and enlightening. It provides so much more than the last repot which was over seven years ago. We have to be thankful that there are so many researchers out there collaborating to bring us this knowledge and then we have to hope that governments and industry listen and take a stand for the future not just the right now.

I’ll leave you with this image. On the left are projected temperature increases if we impose mitigations and on the right is the same map but if we impose none. That is something to think about and make us want to act for sure.

Change in average surface temperature (1986–2005 to 2081–2100) Left: With Substantial Mitigation. Right: Without Mitigation. (Graphic: IPCC).

Change in average surface temperature (1986–2005 to 2081–2100). Left: With Substantial Mitigation. Right: Without Mitigation. (Graphic: IPCC).

So what do you think? Will it make a difference? Will governments listen? Is everyone ready to step up?


One thought on “The IPCC Fifth Assessment Report is OUT!!

  1. Pingback: Positive News For Antarctic Sea Ice | Deep Blue Conversations

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