EXPERT REACTION: One of the next 5 years is set to be the hottest on record, says WMO report

As we continue to emit greenhouse gases at near-record levels, the human fingerprint on the climate becomes stronger and clearer. The world is continuing to warm at a fast pace due to our continuing greenhouse gas emissions, so it's no surprise that we are very likely to see record-breaking global temperatures in the next few years.

The increasing likelihood of a year reaching 1.5C above pre-industrial temperatures is an indicator of how quickly we are damaging the planet. To meet the Paris Agreement and keep global warming well below 2C, humanity must rapidly reduce greenhouse gas emissions. We will only stop warming the planet when we reach global net-zero emissions, so we must work to cut our greenhouse gas emissions as quickly as possible.

When it comes to bushfire risk, the news that there is a 98% chance of setting a new global temperature record in the next five years is extremely worrying. High temperatures are one of the key ingredients for dangerous fire weather, along with dry and windy conditions. As temperatures continue to rise, there is more chance of them coinciding with extended dry spells and droughts. If we continue on our current path there is a real possibility of a repeat – or worse – of the conditions that led to the devastating Black Summer fires of 2019-20. There is still time to avoid the worst climate change projections but it means taking much more action than we currently are.

Faster warming at the poles is precisely what we see in the rock and fossil records from Earth’s deep past. When the world warms, the extra heat is smeared across the globe, with the coldest parts becoming warmer quicker. 

For most of Earth’s history, the planet has been without polar ice caps. But the transitions from an icy world (like today) and an ice-free world is usually much slower. We’re heading towards an ice-free globe, but the rate at which things are changing is reminiscent of the most extreme and most devastating warming events in Earth’s past. 

A small glimmer of hope is that Antarctica is not warming as fast as the Arctic. If this was the case, we would see a dramatic and rapid rise in sea levels, as the land-locked Antarctic ice sheets melted. Instead, we still have (limited) time to avert the worst outcomes of climate change.

Our global Paris Agreement target of 1.5°C was admittedly ambitious, but very few of the relevant scientists think this is realistic anymore. A safer bet would be to prepare for a world that is at least 2°C warmer.

According to the report, there is a high confidence that the world will experience its hottest year on record between 2023 and 2027. Additionally, there is an increasing probability that at least a year during this period will see the annual mean global temperature temporarily surpass 1.5°C above pre-industrial levels.

A possible onset of El Niño is predicted for December 2023-February 2024, which may lead to decreased winter-spring rainfall in eastern and northern Australia, accompanied by warmer daytime temperatures. The combined factors could potentially trigger another drought in the country.

Over the next five years, on average, southern Australia can anticipate warmer temperatures during May to September, while southeast Australia can expect elevated temperatures from November to March, both with a high level of confidence.

The new WMO Report is the latest in a series of expert assessments based on the most comprehensive and rigorous observational data, analysis and modelling that has ever been available.

Key Points about the Science:

The data used cover the entire globe using a combination of surface and satellite-based measurements, and are thoroughly quality controlled by meteorological agencies and scientific researchers around the world.

Climate system modelling by 11 different institutions has been used to produce forecasts for the period 2023-2027, providing a high degree of confidence in the projections because they are replicated across different research groups.  Additionally, testing these models shows that they simulate the observed climate of the recent past to a high degree of accuracy – they work well.

Comments on Key Findings:

Global annual average temperatures are likely to rise to levels never experienced previously by humanity; we are moving further into uncharted territory, in which previous adaptation and coping strategies may not apply.

Global heating is accelerating. The chance of exceeding 1.5°C was nearly zero in 2015, and 10% up to 2021. It is now 66%.

Rapid Arctic warming is a destabilising influence on weather patterns, leading to increasing frequency of extremely hot and extremely cold weather events. It also has global consequences for future weather and climate disruption.

For Australia the projections for the period 2023-2027 show that above-average temperatures are highly likely and there is tendency towards below-average rainfall across the continent, although climate variability from year to year and the likelihood of extreme events (possible drought, severe storms, flooding) are continuing to increase.

Projections for the warmest year on record in the next five years spells further trouble for the health of people around the world. We know that climate change negatively impacts health in a variety of ways, including through the direct physical effects of heatwaves, such as heat stroke, and indirect effects of rising temperatures, such as contributing to food and water insecurity. Exposure to heat also impacts on labour productivity, particularly for people working in agriculture and construction. High-risk populations, such as children, women, the elderly, and people with pre-existing health conditions, can be disproportionally affected by rising temperatures, and at 1.5C, people living in urban areas are more likely to be exposed to deadly heatwaves because of urban heat island effects. We must continue to pursue adaptation measures, such as heat early warning systems, which can help to protect people from heat-related illnesses.

In order for one of the next 5-years to not be record-breaking, we would either need: no El Niño events in the next 5-years or a massive volcanic eruption in the tropics, à la Krakatoa in 1883, both of which are extremely unlikely scenarios.

My biggest fear is that we become desensitised to the ever-falling records and forget what these numbers actually mean. 1.5 degrees warming means the Great Barrier Reef probably won't survive this century. That's tragic.