By Dr. John Happs

It is now widely known that there is a complete lack of empirical evidence to show that atmospheric carbon dioxide drives global temperature. Dr. Horst-Joachim Ludecke has demonstrated this fact from readily available data:

Perhaps not as widely known is that, on those rare occasions when atmospheric carbon dioxide and global temperature have tracked closely, it is temperature that drives carbon dioxide levels.

Despite these facts, we are increasingly encountering media reports about how the Intergovernmental Panel on Climate Change (IPCC) warns that we are heading for climate catastrophe if we fail to reduce our carbon dioxide emissions and continue with so-called “business as usual.”

The media inevitably emphasise the IPCC’s computer model projections, referring to one in particular – RCP8.5. So what is RCP8.5 and why do the media and other alarmists like to parade this model at every opportunity?

Model projections of dangerous global warming have failed spectacularly in the past, as demonstrated by Dr. John Christy who compared 32 climate models with observations from satellite and weather balloon data:

But such computer predictive failure is simply brushed aside with alarmists, including many scientists, seeing a need for more urgency. After all, a good deal of their funding depends on a continuation of the climate scare. Fortunately the public is starting to find predictions of global warming Armageddon and warnings about the end of all life on Earth just a little tiresome.

Undaunted, the IPCC has now presented a series of emission scenarios called Representative Concentration Pathways where RCP8.5 is at the (more scary) top-end whilst RCP2.6 refers to a benign, low-end emission scenario:

As expected, RCP8.5 was based on computer modeling that assumed atmospheric carbon dioxide levels would continue to increase, with global temperature in lock-step, should emissions rise dramatically by 2100.

Note that the IPCC has sensibly branded RCP8.5 as being “Highly Unlikely” with the next lower projection being regarded as “Unlikely”. So why wasRCP8.5 mentioned so many times in the 2019 IPCC report?

The RCP8.5 “business as usual” scenario assumes a 500% increase in the use of coal, which no sensible person would see as being likely. In fact the RCP8.5 scenario would mean burning more coal than actually exists on the entire planet.

The RCP8.5 “business as usual” scenario also assumes there will be no improvement in energy technology yet we know there are a number of revolutionary nuclear projects and clean coal initiatives underway.

The RCP8.5 “business as usual” scenario assumes that the population will double to 12 billion by 2100 even though we know that populations fall in those countries that increase their standard of living.

The publication “Risky Business” has the temerity to say (page 14) that the “business as usual” trajectory is our current pathway and it should be noted that the questionable prediction was made that atmospheric carbon dioxide levels will reach 1,000 ppm by the end of the century.

Referring to the following projections as “global emission scenarios” is drawing a very long bow.

RCP8.5 is definitely not business as usual” but none of this is important to those spreading the climate alarmist message. The deliberate use of RCP8.5 represents another excellent example of how climate science has been skewed so the media, vested interest groups and politicians can spread further alarm.

Small wonder then that investigative journalist Donna Laframboise considers that RCP should mean: Ridiculous Climate Prophecy.

Anyone aware of how the IPCC operates and its use of RCP8.5 knows that it was developed and paraded as an outlier whilst UN officials also knew that it would be seen by many as a distinctly possible pathway. In other words RCP8.5 was always an improbable scenario and definitely not a “business as usual” forecast.

Of course this would never bother UN officials. We can be confident they knew that the more realistic predictions would receive little media attention.

Never wanting to let a good opportunity go to waste, UN Officials also knew that few would read and understand the IPCC technical reports so RCP8.5 was unleashed with the most extreme and highly unlikely scenario being widely advertised as “business as usual.”

Not surprisingly, The Guardian’s Jonathan Watts (13th June 2020) was quick to report that:

Worst-case global heating scenarios may need to be revised upwards ..”


Recent modelling data suggests the climate is considerably more sensitive to carbon emissions than previously believed, and experts said the projections had the potential to be incredibly alarming”.

And which experts would those be?

No doubt those climate scientists and others that have embraced the “business as usual” scenario for their own ends. But we know exactly how the game is played with a number of scientists caring little for academic rigour or scientific integrity as long as they can rack up more publications and rake in more research funding.

They take the most extreme scenario knowing that the media and politicians won’t know anything about RCP8.5. They then refer to it as “business as usual” and describe a doom and gloom scenario for their own area of interest, whether this involves polar bears, insect-borne disease, butterflies, bees, coral reefs and – well just about everything is doomed by RCP8.5.

For instance, a senior researcher at the Cold Climate Housing Research Centre warned:

There is a very grave crisis in the Arctic which might only be resolved if the world uses geo-engineering to cool the Arctic and there are drastic cuts in greenhouse gas emissions.”


With business as usual life on earth is largely doomed.”

Myers et al. (2017) looked at climate change and global food systems and the potential impacts on food production and under-nutrition. They concluded that:

Under the high-emissions RCP8.5 scenario, such restrictions on labor during the hottest month become widespread across tropical and subtropical regions by the end of the century.”


A recent study indicates that, as a result of these changes in size and distribution of plankton communities, under a high-emission RCP8.5 scenario, global fish catch potential would decrease by 3-13% by 2050 relative to recent decades.”


In a low-economic-growth/rapid-climate-change (RCP8.5)

scenario, 43% of all countries in the world would be poorer in absolute terms by the end of the century than they are now.”

IPCC Lead Author and serial alarmist, Macquarie University biologist Dr. Leslie Hughes told the ABC’s Leigh Sales:

‘Business as usual’ will give us the warmest planet in human history and create conditions beyond the experience of any humans ever.”

The message that RCP8.5 represents “business as usual” continues to be promoted by a number of other scientists who should know full well that this is alarmist fantasy. Dr. Mark Urban from the Department of Ecology and Evolutionary Biology at the University of Connecticut writes:

If we follow our current, business-as-usual trajectory [representative concentration pathway (RCP) 8.5; 4.3°C rise], climate change threatens one in six species (16%).”

Dr. Matt Collins, Professor of Climate Systems at Exeter University, promotes a similar view:

The scenario with the most warming is the “business as usual” RCP8.5, in which global mean temperature could be 4°C or more above pre-industrial times.”

Im et al. (2017) in their article: “Deadly heat waves projected in the densely populated agricultural regions of South Asia.” write:

On the basis of an ensemble of high-resolution climate change simulations, we project that extremes of wet-bulb temperature in South Asia are likely to approach and, in a few locations, exceed this critical threshold by the late 21stcentury under the business as usual scenario of future greenhouse gas emissions.”

Mora et al. (2015) also jumped on the “business as usual” bandwagon, writing:

We show that although the global mean number of days above freezing will increase by up to 7% by 2100 under “business as usual” (representative concentration pathway [RCP] 8.5), suitable growing days will actually decrease globally by up to 11% when other climatic variables that limit plant growth are considered (i.e., temperature, water availability, and solar radiation).”

Of course we can expect UN officials such as IPCC Chair Ottmar Edenhofer to refer to RCP8.5 as the “business as usual” scenario. He has made clear his views on the real purpose of climate policy:

Edenhofer argues that: “We are far away from a departure of the business-as-usual scenario.”


Even for 2.5C we need always a fundamental departure from the business-as-usual, and we can discuss now what can we do to find that effective entry point.”

Dr. Bob Jackson is Chair of the Global Carbon Project that leads the research tracking worldwide emissions levels. He was asked:

Are we currently on the worst-case scenario for climate change?”

Not surprisingly, he responded:

We’re actually a lot closer than we should be; I can say that with confidence.”


Under RCP 8.5, the world’s average temperature would rise by 4.9 degrees Celsius, or nearly 9 degrees Fahrenheit. That’s an inconceivable increase for global temperatures-especially when we think about them being global average temperatures. Temperatures will be even higher in the northern latitudes, and higher over land than over the ocean.”

Oliver et al. (2015) looked at the effects of climate change and habitat fragmentation on drought-sensitive butterflies and concluded:

Climate change is expected to increase the frequency of some climatic extremes. These may have drastic impacts on biodiversity, particularly if meteorological thresholds are crossed, leading to population collapses. Should this occur repeatedly, populations may be unable to recover, resulting in local extinctions.”

They then throw in the inevitable:

Under RCP8.5, which is associated with ‘business as usual’ emissions, widespread drought-sensitive butterfly population extinctions could occur as early as 2050.”

Pal and Eltiahir (2015) see problems for human adaptability with the “business as usual” scenario:

We project using an ensemble of high-resolution regional climate model simulations that extremes of wet-bulb temperature in the region around the Arabian Gulf are likely to approach and exceed this critical threshold under the business-as-usual scenario of future greenhouse gas concentrations. Our results expose a specific regional hotspot where climate change, in the absence of significant mitigation, is likely to severely impact human habitability in the future.”

Pal and Eltiahir specifically point out that RCP8.5 represents a “business as usual” scenario,

Dr. Roger Pielke has observed how the Climate Impact Laboratory has also quoted RCP8.5 as representing a “business as usual” scenario, focussing on extreme outcomes such as:

1.5 million people may die in India by 2100 due to extreme heat by climate change.

Rising sea levels could swamp major cities and displace almost 200 million people.

The rise in climate-related deaths will surpass all infectious diseases.

Pielke notes that his search of academic citations (using Google Scholar) provided a record of more than 4,000 academic papers that have deliberately used RCP8.5 as representing a “business as usual” scenario.

No surprise then that the “polar bears are doomed” brigade have jumped on to the RCP8.5 “business as usual” scenario.

Polar bear numbers have climbed from around 7,000 in the 1950’s to more than 30,000 today, largely due to the 1972 Marine Mammal Protection Act and the 1974 International Agreement for the Conservation of Polar Bears.

Ignoring these facts, the BBC continues to provide polar bear alarm, reporting:

Polar bears will be wiped out by the end of the century unless more is done to tackle climate change, a study predicts.”

Left out of the BBC’s report was the fact that the study they quoted used the ridiculous RCP8.5 “business as usual” scenario.

The deliberate misuse of RCP8.5 is widespread and it is virtually certain that any media or “scientific” report that serves up dire warnings about future climate catastrophe will be referring to the “business as usual” RCP 8.5 model. More examples of this sleight of hand can be found at:

Many scientists know full well that predictions based on RCP8.5 are fanciful but very few have raised concerns. Papers that have been published should have been diligently peer-reviewed and the RCP8.5 fraud exposed. This has not happened and the dishonesty continues.

Fortunately we now have a few frank comments emerging about RCP8.5 with Dr. Zeke Hausfather from the Breakthrough Institute in Oakland, California and Dr. Glen Peters from the Center for International Climate Research, Oslo, Norway criticising the alarmists:

RCP8.5 was intended to explore an unlikely high-risk future.But it has been widely used by some experts, policymakers and the media as something else entirely: as a likely ‘business as usual’ outcome. A sizeable portion of the literature on climate impacts refers to RCP8.5 as business as usual, implying that it is probable in the absence of stringent climate mitigation. The media then often amplifies this message, sometimes without communicating the nuances.”

To its credit, the UK’s Meteorological Office has attempted to put the record straight saying:

Despite not being explicitly designed as business as usual, RCP8.5 has often been misrepresented as the “business as usual” scenario – becoming the basis for hundreds of predictions about our certain doom from climate change.”

The corruption of climate science and the unnecessary alarm about catastrophic anthropogenic global warming has occurred because many of our scientific institutions have failed to apply due diligence on this issue.

It has occurred because a number of our universities have encouraged and even vigorously defended climate alarmism since such alarmism has been good for business.

It has occurred because the peer-review process has failed to question the climate alarmism promoted in so many papers and it has failed to identify obvious methodological errors. There is evidence of “pal-review” allowing this.

In summary, it has occurred because money, politics and ideology have corrupted climate science and has brushed aside academic standards and scientific integrity.

There is no doubt that RCP8.5 results are deliberately used to induce “climate hysteria” and Matt Ridley probably best sums up the problems with RCP8.5 when he writes:

What is more, in the small print describing the assumptions of the “representative concentration pathways”, it admits that the top of the range will only be reached if sensitivity to carbon dioxide is high (which is doubtful); if world population growth re-accelerates (which is unlikely); if carbon dioxide absorption by the oceans slows down (which is improbable); and if the world economy goes in a very odd direction, giving up gas but increasing coal use tenfold (which is implausible).”

Dr. John Happs M.Sc.1st Class; D.Phil. John has an academic background in the geosciences with special interests in climate, and paleoclimate. He has been a science educator at several universities in Australia and overseas and was President of the Western Australian Skeptics for 25 years.

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