Where are we on climate change?

Professor Sir Brian Hoskins, Director of the Grantham Institute for Climate Change and advisor to the UK government through the Committee on Climate Change, recently gave a talk at Imperial College London on the latest research and actions around climate change.

Global CO₂ levels are currently at 397ppm (parts per million), a level not seen for 4.5 million years. We have increased CO₂ levels in the atmosphere by 40% since the Industrial Revolution. While there has been a clear and significant increase in global temperatures since 1850, we have seen a hiatus on temperature rises in the last decade. While sceptics may use this as evidence to support their claims, a decade of cooler temperatures is not outside the range of predictions from climate models.

Global sea levels are rising 3mm per year. While the melting of the Western Antarctic and Greenland ice sheets is contributing around 1mm of this increase, it is unknown how likely this is to accelerate if we reach a threshold point of destabilisation. In the Arctic, recent pictures of the ice cap in mid-September (when it is at its minimum size) show it is half the average size it was in the last century. By 2050-2060 we would expect the arctic ice cap to have vanished come September.

We have seen some significant heat extremes in the past decade: the 2003 European heatwave, 2010 Russian heatwave and more recently the 2012 US drought. Work by NASA scientists Dr James Hansen and colleagues indicates a shift to more frequent and severe bouts of high temperatures. But it is not just heat extremes, as the climate changes we are also seeing cold extremes in certain locations despite remarkable warmth elsewhere. This indicates our ability to predict regional trends is much more limited than our ability to predict global averages and while we may, in the past have viewed climate change as a warming of the planet, now we are trying to understand it as a disruption of our climate systems, one that will have severe and varied results.

As we look to a new Intergovernmental Panel on Climate Change report due in September 2013, the next round of data projections for climate change are emerging. The highest emission scenarios, which reflect our current trajectory, predict a global average temperature increase of 4°C by 2100. As an average this means some places won’t see this degree of warming while others will see substantially more. Winter in the northern hemisphere can expect temperatures 10°C higher. In India where temperatures are already over 40°C pre-monsoon, an additional 5°C will have a huge impact. And there are knock-on effects of temperature rises and changes in temperature variants between places. In the UK, for example we might expect stronger storms and heavier rainfall while storms on the other side of the Atlantic may lessen in severity. Changes in rainfall can have dramatic effects for example in the Mediterranean, south-west USA, Australia and southern Africa, major food producing regions that will see a decline in precipitation.

As Prof. Hoskins explained, climate change is a multiplier of stress. We are already seeing the impacts of rapid population growth, of resource scarcity, migration and of hunger. Climate change will make all of these worse.

So the future predicted under climate models appear dire and just to make matters worse these impacts are what we’ll get if we’re lucky. Climate models don’t take into account threshold behaviour, that once a system passes a certain point its behaviour becomes unpredictable and it can deteriorate rapidly.

So we are doing something very dangerous to the climate system with some known but many unknown impacts. This begs the questions what can we do about it. Prof. Hoskins laid out three solutions:

1)     Do something else to the climate systems to compensate. Commonly referred to as geo-engineering, some of the solutions proposed include:

1.  Carbon dioxide removal – from the atmosphere, by fertilising oceans or by storing carbon in the land.
2. Solar radiation management – instead of reducing the emissions of gases which trap heat in the atmosphere we could reduce the amount of solar energy reaching the atmosphere i.e. giant umbrellas in space that reduce the amount of sunlight penetrating Earth; mimicking the particles released by volcanoes that stop some solar radiation by releasing them via rockets over the tropics; using ships to suck water from the oceans and create droplets released into the atmosphere generating more low-level clouds.

These solutions are limited in their effectiveness: only operating in certain areas, cost a great deal and once started must continue for thousands of years to avoid the problem indefinitely. Issues around displacement effects, modifying the weather in one place only to cause problems elsewhere, also dampen enthusiasm for these solutions.

2)     Adaptation. We must adapt. Even if we reduce greenhouse gas emissions today we can still expect to see the impacts of climate change. But what are we adapting to? As stated, regional projections of climate change are weak so we must use past and present data to inform decisions at the same time as learning to deal with different time-scales for decision making and significant levels of uncertainty. If we look at the past, say floods in the UK or hurricane sandy in New York it is clear that we are not resilient to the weather effects climate change is likely to bring. Another question is, to what extent and for how long can we adapt and still live the life we want to live? This all depends on where you live. For people in Bangladesh or on Pacific Islands they may be past the point of adaptation, climate change for them is likely to mean mass migration, something other countries are certainly not prepared for.

3)     Lastly, there is mitigation. There is still hope that the UN Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol will yield results (although we’re not holding our breath). The European Union, hailing itself as a leader on tackling climate change, has backtracked under the financial crisis in the Eurozone, and recently voted not to back the Emission Trading Scheme (ETS). But it’s not all negative. In a recent study of 33 countries, 32 had significant climate change related laws while 18 had made significant progress on reducing emissions. China has an ambitious 5 year plan, is piloting 9 ETS schemes and is growing a climate technology industry. The UK’s Climate Change Act has a target of an 80% reduction, on 1990 levels, of CO₂ by 2050 and legally binding carbon budgets, which prevent governments leaving all reductions activity until 2049. The 4^th carbon budget will be reviewed this autumn and, while there is the danger that the UK could use the EU’s weakness to not meet this budget, we hope that the UK keeps it promises or it risks never getting back on track to meet its goals.

While some progress has been made in reducing emissions, on a consumption basis in the UK, emissions have increased. These emissions are very hard to measure as we are purchasing products manufactured and produced all over the world. But UK businesses are taking climate change seriously and are calling for governments to provide the enabling environment that allows them to make serious changes.

In terms of agriculture, where nitrous oxide (N₂O) and methane (CH₄) rather than CO₂ are the dominant greenhouse gases, very little action is being taken. There is no real measurement for non-CO₂ gases or plan for reducing them, despite agriculture’s contribution to global greenhouse gas emissions being some 30%.

A key question raised at the talk was whether climate change deniers will be won over by the science? Prof. Hoskins thought this was unlikely unless the models discover a threshold e.g. the Indian monsoon will fail by 2040 unless we take action. This may be important to spark significant adaptation activity but mitigation is harder. Many climate change sceptics persist with an argument that any constraint on the activity of an individual is wrong.

It seems that we are at a standstill. We know, on a global scale, what the likely impacts will be and we have a series of solutions that combined could have a large impact. What we are missing is the public support and political will to make it happen. The recent UNFCCC climate negotiations in Bonn were a step in the right direction. The ideas of a ‘spectrum of commitments’ (national-led plans for reducing emissions combining to a formal agreement), of increasing countries’ emissions reduction targets, and of making the 2015 international climate agreement equitable were all discussed. But the talks, while heading in the right direction, leave many questions unanswered and we will have to wait until COP19 in Warsaw to know if any will be (sufficiently) answered.