October 8, 2018

IPCC Global Warming Special Report 2018 | What does it actually mean?

If the global temperature rises by 1.5°C, humans will face unprecedented climate-related risks and weather events.

We are on track for a 3-4°C temperature rise.

It’s the final call; the most extensive warning thus far on the risks of rising global temperatures.

What is the Intergovernmental Panel on Climate Change (IPCC) Report?

The 2018 IPCC report1 is the most up-to-date and comprehensive explanation of the science of climate change and the future of Earth.

91 lead authors and 133 contributing authors, from 40 countries, assessed 30,000 scientific papers and made over 42,000 comments during the review process.

Their findings cannot be ignored.

Prepared by leading researchers from around the world, the report was delivered to governments, policy-makers and individuals in Korea on Monday 8th October. It warns that the world has already warmed by 1°C since the middle of the 19th century, and could reach 1.5°C before the middle of this century at the current rate of warming2.

The change caused by only just half a degree came as a revelation, the difference is substantial and demands action.

It’s scientists’ way of using numbers, diagrams, and modelling to say that the whole world, at a global and individual level, must take action now.

It sets the world a clear target. We must reduce emissions of greenhouse gases to net zero by the middle of this century to have a reasonable chance of limiting global warming to 1.5°CThis thunderous call to action lays out the tools we have at our disposal to mitigate climate change, sequester carbon emissions and steer the future of Earth in a direction we can live with.


It’s yet another wake-up call.

One of the main findings is that we are on track for 3°C rising. Limiting the rise to 1.5°C will require immediate action, and still create climatic difficulties but will have markedly better results for the planet.

Staying below 1.5°C will require “rapid, far-reaching and unprecedented changes in all aspects of society.”

“Adaptation is expected to be more challenging for ecosystems, food and health systems at 2°C of global warming than for 1.5°C,” according to the IPCC.


Is there actually that much difference between 1.5 °C and 2 °C temperature rise?

Half a degree may be the difference between a world with coral reefs and Arctic summer sea ice, and a world without them4.

Carbon brief showing 1.5/2 degree

What happens if we don’t take action?

It’s key to remember that we tend to talk about climate change in terms of averages, at the global level. However, masked in those averages are extremes: more frequent and intense heat waves, more damaging storms, higher oceans. The world, and its people, will be affected disproportionately. At the local level, the disparity is great.

And those least able to adapt will face the greatest impact.

We have to act now. The warming effect of increasing carbon dioxide takes decades to influence the planet’s temperature. Even if we cut all emissions today, we are still set for a temperature rise, due to the cumulative effect of the climate. To meet a goal of 1.5 °C warming, this demands immediately cutting the planet’s emissions to 45 % below 2010 levels by 2030.Graph showing emissions trend and temperature overshoot

Understanding the IPCC Special Report, 2018


What are the key points from the report?

42 Human activities are emitting 42 billion tonnes of carbon dioxide every year.
20 At this rate the carbon budget, allowing us a 50:50 chance of keeping warming to 1.5°C, would be used up within 20 years.
2050 Limiting global warming to 1.5°C, compared with 2°C, could reduce the number of people both exposed to climate-related risks and susceptible to poverty by up to several hundred million by 2050.
1.5 Limiting warming to 1.5°C is not impossible but will require unprecedented transitions in all aspects of society.
1 Temperatures have risen 1°C since the 1850s. Every bit of warming matters.
1.5 Current pledges by world governments are not enough to limit rises to 1.5°C.
45 We need to cut global emissions by about 45% by 2030 compared with 2010 levels.
4 The world is currently on a trajectory of 3°C to 4°C rise.

“The report will encourage the development of new technologies, which is important. However, time is running out, so we must capitalize and build upon the solutions available today.”

Former Vice President Al Gore on the IPCC Special Report on Global Warming

What can we do now?

It isn’t always easy to be optimistic when faced with reports like this. But, a recent UN emissions report proposes, in order to achieve the long-term goals of emission reduction, encouraging optimism, scaling up existing solutions rapidly, and using science to guide targets. Three things Cool Earth is all about.

However, we need to listen to the extreme forecasts being forecasted by leading scientists in the IPCC.

In order to stay below our current 3ºC trajectory, we require urgent, large-scale changes from both governments and individuals. It also recommends investing a lot of money in mitigation methods: around 2.5% of global GDP for two decades.

By combining land use and technological change, reduced deforestation and movement towards completely renewable energy, we can reduce emissions and increase carbon sequestration.

Trees are hugely efficient carbon stores, with an acre of tropical rainforest storing 260 tonnes of carbon. But it’s not just about carbon. They are home to wildlife, essential in the global water cycle, reduce soil erosion and essential for indigenous cultures around the world.

Several pieces of research continue to point to rainforest being key in the future of carbon mitigation. In fact, rainforest is so effective at storing carbon, you’d have to recycle four million aluminium cans to have the same impact as protecting an acre. We need to make rainforest protection as key a part of our lives everyday as recycling has become.

IPCC Global Warming Special Report 2018 | What does it actually mean?
  1. IPCC, 2018

  2. Vox, 2018

  3. Guardian, 2018

  4. New York Times, 2018


  • Excellent article, clear and concise and very well explained.

    Scary though and frustrating as this is still not a priority with most governments in the world. Governments that are incapable of reacting to the altruistic needs of nature and humanity instead stuck in the claws of the fiscally motivated.

  • David C. Smith,PhD says:

    experimental data does not support the assumption that man’s carbon emission is the cause of global warming (GW)..

    1. The increase in atmospheric CO2 from 320 ppm to 400 ppm is predicted to cause a 0.75 to 1,25 degree C by man generated GW where experimentally the measured temperature rise of 0.25 deg C.

    2.the thermal heat leaving the earth is experimentally measured to be increasing with earth’s temp. rise. All of the models of man caused GW predict a decrease.

    3.Past records of GW as measured by ice core sampling show a correlation between atmospheric aerosol increases and global warming cycles every 100,000 years for the past 500,000 years. The aerosol increase changes the albedo of the northern global ice cap and leads to GW. The numbers on this effect support it’s cause of GW . No direct experimental evidence has been found.

    • James Lowe says:

      @David C.Smith. Can you please point me to the sources you got this information from? I’d like to learn more.

    • HAZ JO says:

      Dear David, your comments are very interesting as you mention experimentation approach but none can believe you if you don’t show references. However, on my behalf you should at least be worried about the human population increase since 1960s at least and their activities changing the natural environment for infrastructure, energy requirements, food production, waste disposal…as the world development goes on. What do you think of their impact Sir? I think it doesn’t require thinking much to be aware of the change. It is obvious that a change might occur and the scientists do their job just to detect the change, find cause and and quantify the impact. Rather you’d better take part with your good project in environmental protection and contribute to the slowing down the global warming rate.

  • David C. Smith,PhD says:

    I posted a comment that gave a list of experimental results that refute man’s contribution to global warming. you erased it from your comments. Are you opposed to any comments that don’t agree with your position?

    • Chloe Rickard says:

      Hi David,
      We didn’t erase your comment made on October 9th. We moderate all comments and only delete those which are spam or contain offensive material. As we are a small team we are unable to moderate comments immediately which is why there is sometimes a delay in posting. Apologies for this.
      Chloe Rickard
      Senior Communications Manager

    • Andrew MacGowan says:


      Mechanical engineer here from Oxford. Just wanted to analyse a couple of things in Davids first comment that made me raise an eyebrow, so that
      people reading this in the future can have an opposing opinion to bounce off.

      Apart from every grammatical error in his comments I’d first like to point out to everyone that no sources were given behind this guys
      statements; yet he apparently “refuted”, or disproved everything that these 91 top climate scientist have said. There’s a common argument in philosophy which applies here and it goes along the lines of, ‘whichever option was the lesser miracle, probably happened’.

      In other words, which was the lesser miracle – that David had his (unreferenced) facts wrong, or that 91 top climate scientists working for years on a report, going through literally 30,000 research papers got everything that they did entirely wrong and were actually pretty dumb?

      Let’s have a look at point 1.

      “The increase in atmospheric CO2 from 320 ppm to 400 ppm is predicted to cause a 0.75 to 1,25 degree C by man generated GW where experimentally the measured temperature rise of 0.25 deg C”.

      There isn’t a reference given, so he could have made this up; as a research student I’m instantly skeptical.

      Maybe he’s trying to say our current model of the temperature increase is wrong. Sorry David I’m gonna have to one up you – every model in science is wrong.

      Unless you want to model every single atom in the universe at once on a computer (that’s impossible), we have to make assumptions and approximations about what is going on, that’s why we call it a model. We lose maybe 5 – 0.0001% accuracy here in the assumptions generally, and if we can’t get it this accurate then we make a new model that can. Models work; it’s what gets houses and pipes built, planes and cars, and it’s what lets us predict collisions to within tiny tolerances at places like CERN. When you get a model massively wrong it’s pretty easy to notice in your maths, what he’s saying is that 91 climate scientists assessing 32,000 papers, each requiring hundreds of hours of work all have maths mistakes in them.

      That’s beyond unlikely; to all intents and purposes that’s impossible.

      What timeframe is this temperature rise given over? Which two temperature rise predictions is he comparing? He might be comparing a temperature
      rise from 2005-2010 with a predicted rise from 2000-2005 and saying that they should be equal, which doesn’t make any sense to do.

      When was this temperature rise predicted? It doesn’t make sense to quote a model that predicted this in 1980, our models are constantly being updated and improved with new computer technology; of course older models are going to get things a little wrong over a long timescale.

      Who made this prediction? My grandma can predict temperature rises. It doesn’t mean that she’ll be correct.

      There’s endless questions raised here and we can’t conclude anything from this first statement.

      Moving onto the second point, when we talk about heat in thermodynamics (the study of heat flows and energy) we really mean a flow of energy
      between two places; a flow of heat energy. This is a thermodynamic issue at hand here; there’s more heat going in (or being generated) than going out, and that’s what is causing the temperature rise.

      It makes literally no sense to talk about “thermal heat”, it’s like saying “hot hotness” or something; its fair to suggest that this man might not be well acquainted with thermodynamics. His PhD may be in another subject, or maybe that PhD doesn’t exist; we can’t know for sure (we always need to remind ourselves of these things on the internet).

      Still on the second point, if “all of the models” of man-made climate change predicted a decrease in temperature, how did the report David is literally commenting on, after collating information from 30,000 reports, come to conclude that the models of man-made climate change predicted an increase in temperature instead? Moving on.

      I don’t even understand the third point he made. So there’s a correlation seen in experiments between aerosol increases and global warming due to the libido effect, cool, and it says again that the numbers from experiment show that it’s due to GW, but the paragraph ends saying that there’s
      no experimental evidence. Erm. What?

      In the second comment he asks about being opposed to opposite opinions; debate isn’t about sensationalist comments like this, it’s not about
      winning, it’s about respect and learning with other people. David clearly hasn’t respected the scientific community here, and instead decided to spew a list of non sequiturs at us. I wouldn’t be surprised if someone removed a comment like this if it made this little sense and only contributed to confusing people who are new to the issue of climate change.

  • Dave Jordan says:

    There is a great divide in the argument as to whether humans have caused climate change through global warming, this argument we do not enter. However, there can be no argument to the effect of humans on the state of the environment through consumer product, By changing what we make products from, petrochemical to plant based, we will eventually clean the environment. By doing so we will have healthier life on earth. So that then if global warming was a human issue a shift in the climate might occur. If not at least we have a cleaner environment. The choice is ours to action or debate.
    If only talk continues then we are at the mercy of chance. My company is answering the call to action
    Dave Jordan Founder/CEO
    Hemp Farm New Zealand Limited

  • steve walton says:

    global warming and climate change is a major issue for todays life and tomorrow future ,If we want to save our future we have to take care of our nature from heavy pollution and over population of some countries.

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