‘Be alert, but not alarmed’
‘Be alert, but not alarmed’ – we often hear this advice about how to respond to crises. It’s usually best to be calm, observant but not over-anxious, so that we can sleep at night and make rational, well-considered decisions. Would we have quoted this advice in England during World War II as bombs were falling on cities? Or during recent bushfires in Australia? I don’t think so – alarm was appropriate for spurring people into immediate action to protect themselves and their loved ones.
A recent letter from a reader of Insights criticised ‘climate alarmism’ as denying the poor a means to generate cheap, reliable electricity (from coal). But in the case of climate change, I think alarm is appropriate – we certainly need to take immediate action which goes against our natural instincts to continue business as usual.
Let me explain why I think the situation is so serious, from my perspective as a scientist and a Christian. But first, how sure are we that the problem really exists?
We hear a lot about climate change, and how greenhouse gases are warming the atmosphere – how climate change is responsible for the latest cyclone, flood or drought. These things are doubted and debated, especially when cold weather arrives. We are reminded that the weather is always changing, and the climate has been changing for millions of years – so what’s the fuss? It is a bit like when medical scientists first warned of the dangers of smoking – these warnings that were immediately rebutted by arguments such as, “Well my grandfather smoked until he was 90, and he was OK.” Many arguments refuting the science have been promoted by organisations with vested interests – which bears a striking resemblance to the climate change debate . Our judgement can be influenced by our values, our wish to justify our own lifestyles and by events that do not support the overall statistical trend.
What many of the public don’t realise is that, for climate scientists, there is abundant unequivocal evidence that the climate is changing, that the changes are caused by human activities, and that the changes are going to be very serious. For example, there is no doubt that:
- Carbon dioxide is a greenhouse gas – that is, it absorbs infrared energy (radiated heat) emitted from the earth, reducing the amount of energy that can escape. Raising levels of greenhouse gases tips the balance – more of the sun’s energy enters the earth than can leave, warming the atmosphere and the oceans.
- Carbon dioxide levels have increased from around 280 parts per million (ppm) prior to industrialisation, to around 400 ppm today, a level that is probably higher than at any time in the last 2 million years .
- Measurements of carbon isotopes indicate that the carbon added to the atmosphere comes from non-volcanic carbon that has been buried underground for a very long time – i.e. fossil fuels . That is, this change in the atmosphere can be attributed to human activity.
- Global average temperatures are increasing. 2015 was the first year that the average temperature reached 1°C above pre-industrial levels . While average temperatures go up and down from year to year, the warming trend is clear. Of the 16 hottest years on record, 15 have occurred in the 21st Century .
- Over geological timescales, changes in carbon dioxide levels have been accompanied by changes in temperature (and vice versa) and large changes in sea level (many metres). These quantities are tightly coupled, according to observations and calculations . There is no reason to expect it to be different this time around.
There is plenty of other evidence of anthropogenic (human-caused) climate change that we don’t have time and space to go into now – please look at the references for further information.
Now let me describe the three aspects of climate change that concern me the most:
1) Temperatures and human survival. In the tropics, temperature and humidity are close to the limits of human tolerance. Anatomical studies indicate that humans cannot survive wet-bulb temperatures of more than 35°C, which is only about 4 degrees warmer than wet-bulb temperatures observed in tropical areas . With projected temperature increases of 3 to 4 degrees by the end of the century, millions of lives are likely to be in danger if we continue our business-as-usual practices .
2) Sea level. Sea levels around the world today are, on average, around 24 cm higher than they were in 1880 . Long-term sea level rise is caused mainly by the melting of ice sheets and glaciers and the thermal expansion of the ocean. Measurements indicate that sea levels are rising at an average rate of more than 3 mm per year . So, how much will sea levels rise in the future?
During the last ice age, when the global average surface air temperature was only about 5 degrees cooler than current temperatures , extensive ice sheets spread across North America and Northern Europe, robbing the oceans of some of their water. Consequently, sea levels dropped to 120 metres below current levels . So, if the air temperature now increases by 1, 2 or 5 degrees, we can expect the long-term sea level rise to be many metres, although there is not enough land ice to melt to cause a 120 metre sea level rise.
A study by Benjamin Strauss et al. from Climate Central estimates that unabated carbon emissions up to the year 2100 would commit an eventual global sea-level rise of 4.3–9.9 m . A further report based on this work predicts, ‘Carbon emissions causing 4°C of warming — what business-as-usual points toward today — could lock in enough sea level rise to submerge land currently home to 470 to 760 million people, with unstoppable rise unfolding over centuries. At the same time, aggressive carbon cuts limiting warming to 2°C could bring the number as low as 130 million people.’ 
These changes are already starting to happen, as witnessed by our neighbours in low-lying Pacific islands. It may take centuries for the waters to reach the predicted levels that will inundate large cities and displace hundreds of millions of people. Is this a reason for us not to be concerned?
3) The ocean. The ocean is a life support system for humanity, storing and recycling our water, absorbing our waste, regulating air temperatures and providing us with 50% of our oxygen . Marine ecosystems provide much of the world’s food and are vital for the web of life that we are a part of.
The ocean absorbs more than 90% of the additional heat caused by greenhouse warming ; that is why air temperatures have risen only 0.85 to 1°C since pre-industrial times. Things could have been a lot worse for us.
Two major changes in the ocean attributable to climate change are:
- Warming of the ocean. The globally averaged sea surface temperature has increased by approximately 0.6°C since 1880 . Warmer waters lead to greater moisture content in the air above the water and potentially more severe tropical storms, as we have witnessed in recent years. Changing the water temperature also causes coral bleaching and alters the mixture of species that can survive in the water. Warmer waters hold less oxygen, impacting on the marine food chain from tiny zooplankton through to large predators .
- Ocean acidification. Increased carbon dioxide levels in the ocean have raised the acidity (or hydrogen ion content) of the ocean surface by almost 30% , a figure which is likely to increase substantially this century. This change makes life difficult for marine creatures such as corals, shell fish and animals with exoskeletons (e.g. prawns/shrimps); they rely on calcification to form their shells, which requires a slightly alkaline environment. If they cannot form shells properly, their growth and survival are placed in jeopardy, threatening ecosystems such as the Great Barrier Reef and deep-water habitats in the Southern Ocean .
Messing with the temperatures and chemistry of the ocean is like playing Russian roulette with this marvellous, complex, God-given life-support system.
Paris Climate Conference and beyond…
The Conference of Parties (COP 21) in Paris in December 2015 was a meeting of representatives of nearly 200 countries to agree on the way ahead to tackle climate change. The French organisers did a brilliant job, with years of careful planning, behind-the-scenes negotiation and pre-organised voluntary pledges put forward by 146 of the participating nations, outlining what they plan to achieve. A historic agreement was made to for the world to hold the increase in the global average temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels, recognising that this would significantly reduce the risks and impacts of climate change.
I was personally delighted with the outcome of the conference. It achieved an agreement which was bolder than I expected, an agreement between all the participating nations that went far beyond the achievements of previous international climate change conferences.
Will the Paris agreement solve our climate change problems? No – far from it . Even if all the countries attending the conference do what they have pledged to do (and this seems unlikely), the things that they have promised to do will not limit global average temperatures to 1.5 or 2°C. Climate scientist have estimated that we are on-track for a 3 or 4 degree temperature rise above pre-industrial temperatures, in this century.
Because of this, James Hansen, the ‘father of climate change awareness’, called the Paris climate talks ‘a fraud … no action – just promises. As long as fossil fuels appear to be the cheapest fuels out there, they will be continued to be burned’ . Indeed, the conference spoke more about the aspirations of the nations than concrete plans to achieve these results. The recent announcement by the CSIRO that it will disband its climate research highlights Australia’s ability to say one thing among the international community (that we will strengthen our climate science) and do the opposite back home .
An article by ANU climate scientist Andrew Glikson  highlights the dilemma: ‘The warming target of <1.5C has already been breached over the continents and a global ~2C temperature rise is only masked by the reflective albedo of transient sulphur aerosols.’ In other words, if we were to clean up the sulphur-based pollutants that are reflecting sunlight entering the earth, our temperatures would already be around 2°C warmer than in pre-industrial times.
Hansen, Glikson and other climate scientists have recognised that in order to stop atmospheric temperatures from continuing to rise we need to STOP putting greenhouse gases into the atmosphere. Not just reduce our emissions by modest amounts; we need to stop emitting. And we need to do it this century – preferably by 2050 . There is no time to waste.
With our whole society dependent on burning of coal, oil, gas, diesel, petrol and aviation fuel, what hope do we have of change? It will take years to change our practices. But change is possible. Renewable energy technologies are becoming available and more affordable . What about our political will?
To make these changes happen, we will need to make considerable efforts to support the communities that are most affected – those that depend for their existence on the production of fossil fuels, as well as those impacted by climate change. These changes won’t be easy, but I believe they will be worthwhile for everybody, in the long run.
So, should we be alarmed? If ‘alarmed’ means being shaken out of our complacency to take drastic action, then I think that alarm is exactly what we need. But if ‘alarmed’ means being paralysed with fear, then the answer is no.
We should not be afraid. Jesus assured us that he will be with us always; we are never alone in the world. The First Letter of John tells us that perfect love drives out fear. Let us be perfectly loving, and bold enough to take action to embrace transition and change, to protect the creation and our fellow human beings.
References/links (active February 2016):
- https://sealevel.climatecentral.org/news/global-mapping-choices; https://sealevel.climatecentral.org/uploads/research/Global-Mapping-Choices-Report.pdf
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