UN warns of possible 3°C temperature rise by 2100

By Dimitris Dimoliatis & Mike Ritchie, MRA Consulting Group

CSIRO and BOM are not the only scientific organisations that have noticed the unusually pronounced weather events around the world. Through long term monitoring key international agencies have also concluded that on a global scale, the past four years (2015, 2016, 2017 and 2018) have been the warmest years on record.

The UN World Meteorological Organisation (WMO), the UK Met Office, NASA and NOAA have analysed global temperatures in slightly different ways and have all, individually, come to that same conclusion.

WMO, who performed consolidated analysis of five leading international datasets of global meteorological and marine observations[1], issued a press release stressing that the pattern of change is more worrying than any one off events. According to WMO Secretary-General Petteri Taalas:

The long-term temperature trend is far more important than the ranking of individual years, and that trend is an upward one. The 20 warmest years on record have been in the past 22 years. The degree of warming during the past four years has been exceptional, both on land and in the ocean.

Temperatures are only part of the story. Extreme and high impact weather affected many countries and millions of people, with devastating repercussions for economies and ecosystems in 2018.

Mr Taalas also stressed that the current trend of record GHG concentrations continue we may see temperature increases 3-5°C by 2100. In fact, the lower end of the range, a 3°C rise in temperatures, assumes that all countries will fully act upon their pledges to meet the Paris targets:

We are not on track to meet climate change targets and rein in temperature increases. Greenhouse gas concentrations are once again at record levels and if the current trend continues we may see temperature increases 3-5°C by the end of the century. If we exploit all known fossil fuel resources, the temperature rise will be considerably higher.

It is worth repeating once again that we are the first generation to fully understand climate change and the last generation to be able to do something about it.

A global temperature increase of 3°C could lead to irreversible sea-level rises that could make coastal cities much more flood prone or even inundate them in the absence of very expensive capital works such as extensive installation of pump stations, expanded drainage systems, elevated roads and building of extensive dyke systems.

Australia’s coastal cities would not remain unaffected. And although, as of yet, there are no plainly visible signs of this, the impacts of climate change are already being felt by everyday Australian’s through extreme weather events.

The WMO report even made a specific mention to the weather we have been experiencing recently:

Australia had its warmest January on record, with heatwaves unprecedented in their scale and duration. Tasmania had its driest January on record, with destructive bushfires. There has been a long-term increase in extreme fire weather, and in the length of the fire season, across large parts of Australia, according to its Bureau of Meteorology.

For some time now, the UN Intergovernmental Panel on Climate Change (IPCC) has been warning that action is needed now to reduce the impact of climate change. According to the Guardian, the IPCC warned that “there is only a dozen years for global warming to be kept to a maximum of 1.5°C, beyond which even half a degree will significantly worsen the risks of drought, floods, extreme heat and poverty for hundreds of millions of people”.

All the while, here in Australia, we continue to go back and forth, swapping politicians over climate policy, dragging our feet as if we have all the time in the world.

But we don’t. What we have is extreme weather, coral bleaching and vulnerable cities. What we do not have is a coherent climate policy including a viable pathway for reducing our emissions and detailed plans for averting the worst impacts of climate change.

As we have said before, these are real issues requiring real solutions. The science is in and the know-how to reducing emissions and minimising the impacts is there. What’s missing is political will.

The government has to review the science, identify the country’s needs and plan for the future accordingly. And level headed politicians from all parties should support these plans based on science and science alone.

As always, we welcome your feedback on this, or any other topic on ‘The Tipping Point’.

[1] WMO uses datasets (based on monthly climatological data from Global Observing Systems) from the United States National Oceanic and Atmospheric Administration, NASA’s Goddard Institute for Space Studies, and the United Kingdom’s Met Office Hadley Centre and the University of East Anglia’s Climatic Research Unit in the United Kingdom.

It also uses reanalysis datasets from the European Centre for Medium Range Weather Forecasts and its Copernicus Climate Change Service, and the Japan Meteorological Agency.  This method combines millions of meteorological and marine observations, including from satellites, with models to produce a complete reanalysis of the atmosphere. The combination of observations with models makes it possible to estimate temperatures at any time and in any place across the globe, even in data-sparse areas such as the polar regions.