Paris Agreement

In hot water: how climate change is affecting the oceans

Perhaps as a result of the nation being gripped recently by the stunning images of Blue Planet II, more and more attention is rightly being afforded to the world’s oceans – and the environmental problems which afflict them. Given the vastness of the oceans, the challenges they face are numerous. Yet one threat, climate change, appears to be particularly acute.

Our species’ centuries-long reliance on fossil fuels to produce energy, as well as trends in animal agriculture and other polluting industries, had emitted greenhouses gases into the atmosphere and changed the planet’s climate. These greenhouse gasses, like carbon dioxide and methane, trap heat close to the Earth’s surface, which have been behind the steady rise in global temperatures.

The impact on marine ecosystems

A changing climate has exhibited itself in several forms across various habitats. One serious manifestation for oceans, however, has been the problem of acidification. This refers to the steady alteration of the chemical composition of seawater, triggered largely by more and more carbon dissolving into the oceans. Since the beginning of the industrial revolution, the pH balance of surface ocean waters has fallen by 0.1. Whilst this may seem insignificant, because the pH scale is logarithmic it actually represents a 30% increase in acidity.

One of the most widely understood impacts of ever more acidic oceans is the effect it can have on organisms known as ‘calcifiers’. These are animals such as crustaceans, molluscs, and corals which use calcium and carbonate ions to build shells and exoskeletons around themselves. But acidic oceans dissolve calcium carbonate, so when the pH level drops, the ability for calcifiers to maintain themselves – let alone grow and prosper – becomes all the more difficult. In addition to this, research has found that successful fertilisation rates for some calcifiers decrease in acidic waters.

Coral reefs are some of the most biodiverse ecosystems in the world. Yet warmer waters present an existential threat to them – with experts claiming that the Paris Agreement’s commitment to 1.5℃ being the only way to save coral reefs. When the waters in which corals are found get too warm, they expel the algae which give them their renowned vibrancy, and turn white. This ‘bleaching’ does not mean the coral is dead, but without the algae corals find it more challenging to survive, and consequently often do die off as a result. Moreover, scientists have observed numbers of certain organisms which predate on corals – such as crown-of-thorns starfish – unsustainably flourishing in warmer waters, which further adds to the struggle to survive for corals.

As the climate warms, and the ice caps melt, sea levels inevitably rise. Indeed, over the past century, it is thought that the global mean sea level has risen by between four and eight inches. Even more worryingly, the rate at which it is has been rising over the past 20 years is double that of the preceding 80.

The consequences of rising sea levels for marine wildlife are multifarious, and will almost certainly result in the destruction of habitats vital for semiaquatic animals. Sea turtles, for instance, which depend on beaches to lay their eggs are one particularly vulnerable species. But one report claims that as many as 233 already endangered species will become further threatened by rising sea levels.

A lesser appreciated consequence of increased ocean temperatures is the effect it has on ocean currents. These currents influence aquatic animals’ migratory patterns, which can disturb ecosystems, as well as dispersing the nutrients vital for life below the waves. Changes in them, therefore, may starve areas of biodiversity of the nourishment necessary to sustain life.

The human cost

Whilst the impact of climate change on the globe’s seas and oceans is tragic enough in its own right, it also poses significant costs which will be borne more directly by humankind, too.

Coral reefs, for instance, are valuable sources of medicinal learning – with drugs to treat cancer, arthritis, and asthma having already been developed from resources found in corals and surrounding ecosystems. Evidence has shown that coral reefs also act as barriers to ocean waves and storms, which provides protection to millions of people the world over. Of course, pristine coral reefs also attract tourists – and are estimated to be worth over £25 billion a year globally, with that money often going into some of the most economically challenged parts of the world. Climate change, and ocean acidification, therefore, imperils all of that. Indeed, it is thought that the Great Barrier Reef is now beyond repair because of this combination of threats.

Changing ocean temperatures which alter currents can also have negative ramifications for people. Ocean currents have two significant roles in the global ecosystem. It has already been considered how they serve as a nutrient dispersal mechanism, shifting food for aquatic species up from the depths and then around the oceans. Warming waters which can decelerate these currents, therefore, could spell bad news for fishing communities who find themselves with fewer fish to catch.

Ocean currents also have an influencing role in local climates. Whilst they do not effect global temperatures per se, currents do facilitate the movement of heat – such as from the warm equator to temperate Britain, East America, and Europe. This partly explains why certain regions on the same latitude experience different temperatures. Were this process to slow down or cease, such aforementioned locations could see their localised temperatures change. 

For many good reasons, some of the most populous cities can be found next to the sea – Shanghai, Miami, and Rio de Janeiro to name but a few. Yet, faced with rising sea levels, their coastal locations could be their very downfall. One estimate places the figure at risk from rising sea levels, and the increased flooding and intensified storms associated with global warming, just shy of two billion individuals.


Seas and oceans cover almost three-quarters of the Earth’s surface. Though often thought to be harsh and uncompromising environments, they contain fragile ecosystems, and have intimately felt the effect of anthropogenic climate change. The future consequences of this are hard to predict, however signs are already beginning to show the costs – for humans and wildlife – of climate change for our oceans.

Eamonn Ives is a researcher at Bright Blue

We’ll always have Paris

This week, delegates from almost 200 countries are gathering in Marrakech for the next round of UN climate talks. There are many reasons for climate diplomats to be cheerful. Last year’s Paris Climate Agreement, signed by all those countries, has come into legal force over a year earlier than planned. All the major emitters, including the US, China, India, and the EU, have now completed domestic ratification of the treaty. The global economy seems firmly set on a trajectory towards net zero emissions by the end of this century.

But despite these successes, there are several major challenges facing attendees in Marrakesh: how to increase individual emission pledges, how to raise sufficient climate finance, and how to respond to President-elect Trump.

Ratcheting up the ambition

Signatories to the Paris Agreement pledged to limit average global temperature rises to well below two degrees and to aim for a rise of just 1.5 degrees. Yet the Intended Nationally Defined Contributions (INDCs), voluntary pledges by individual countries of how much they would cut their emissions, are not sufficient to achieve these high-level goals.

Ahead of the summit in Marrakesh, the United Nation’s Environment Programme released a report on the ‘emission gap’, which is the deficit between the INDCs and the long-term goals. They find that current pledges will lead to an average warming of around 3.2 degrees above pre-industrial levels. They also calculate that, under current INDCs, both the 1.5 and 2 degrees ‘carbon budget’, the total amount of carbon that can be emitted before temperatures rise above a certain level, would be easily exceeded by 2030.

In the text of the agreement, there is a resolution to begin a dialogue in 2018 on progress towards the 1.5 and 2 degree targets. Another key feature of the Paris deal is that signatories must reassess and increase their individual contributions every five years to help ensure the high-level goals are met. The first occasion this will happen is in 2020. So there are mechanisms for scaling up pledges, but urgent progress is required.

Securing climate finance

The support of developing countries for the Paris Agreement was contingent on securing sufficient funding to help them mitigate and adapt to climate change. A total of $100 billion per annum by 2020 must be raised by developed countries. The UK Government this week released a statement showing that funding currently stands at $62 billion per annum, up from $53 billion in 2013. The UK’s own contribution is set to rise to £1.76 billion by 2020.

Donald Trump has said he will cancel the United States’ payments to this fund. President Obama had pledged to give a total of $3 billion by 2020. Assuming Trump follows through with this election pledge, replacement finance will now be required, as well as the outstanding amount.

Managing President-elect Donald Trump

During his election campaign, Donald Trump pledged to withdraw the US from the Paris Agreement. But as the ratification process was so swift, he is unable to cancel the treaty altogether. In fact, reports have suggested the possibility of Trump as President helped instil the urgency to bring the treaty into force. In theory, the US would have to wait four years before it could leave, but in reality, there is little to stop him disregarding the emission reduction pledges made by President Obama. In addition, Trump has promised to “end the war on coal”, and review the current regulations helping to drive coal off the system.

Nevertheless, strong economic forces, as much as political will, are now helping to drive decarbonisation. The rapidly-falling costs of low-carbon technologies have made renewables as cheap as, if not cheaper than, traditional fossil fuels. The International Energy Agency (IEA) reported that costs of onshore wind have fallen by 30% between 2010 and 2015, and those of solar by two-thirds. Independent analysis for the UK Government this week show that onshore wind and solar will both outcompete gas on price by 2025. This may help keep the US, and indeed the rest of the world, on a low-carbon trajectory in the absence of presidential leadership.


Even before the election of Donald Trump, the challenges of matching action with ambition and raising sufficient climate finance were significant. When President Obama hands over to President Trump, an important galvanising force for international climate action will be lost. But other major climate leaders are now emerging. China actually castigated candidate Trump in November 2016 for his intention to withdraw from the Paris Agreement.

Countries like India and China are clear that they are pursuing their own self-interest by championing climate action. Decarbonising helps India to cut its air pollution, with pollution in parts of New Delhi currently five times the level considered safe by the US’s Environment Protection Agency. Similarly, China sees a major economic opportunity both from increased low-carbon infrastructure spending and from becoming a leading exporter of low-carbon technologies.

Post-Paris there is both a political framework for scaling up ambition and an economic imperative to be at the forefront of the low-carbon transition. Despite Trump, the delegates in Marrakech can be optimistic.

Sam Hall is a researcher at Bright Blue

The path to decarbonisation and the fifth carbon budget

By the end of June 2016, the Government must announce the level of the fifth carbon budget. This will set a legal cap on UK carbon emissions for the period from 2028 to 2032.

Five yearly carbon budgets are a key component of the Climate Change Act, and together they plot a route to the 2050 target of an 80% reduction in emissions against 1990 levels. The Committee on Climate Change (CCC) has a statutory duty to advise ministers on the most cost-effective path to decarbonisation. In November 2015, they recommended a 57% reduction in emissions for 2028-2032.

The period of the fifth carbon budget coincides with when the EU’s 2030 emissions target must be met. At the Paris climate summit in December 2015, the EU committed to reducing carbon emissions by 40% by 2030 from 1990 levels. If the UK wants to fulfil this international obligation, therefore, it must ensure that the fifth carbon budget is compatible with what was agreed at Paris.

There has been considerable discussion among Conservative backbenchers about the fifth carbon budget. Two groups of Conservative MPs have written to ministers with contrasting views on the fifth carbon budget. One group has called for the Government to accept the CCC’s decision as soon as possible to send a clear signal to investors. Another has called for the Government to delay the decision to ensure other member states contribute fairly to the EU’s Paris commitment.

The Chair of the CCC, Lord Deben, wrote to the Energy Secretary, the Rt Hon Amber Rudd MP, in January 2016 advising that their recommendation for the fifth carbon budget would be sufficient to meet the EU’s agreed contribution. However, he has also warned that, in the long term, the targets in the Climate Change Act will have to be revised to fulfil the ambition in the Paris Agreement of reaching net zero global emissions by the end of the century. These conclusions were also reaffirmed in April 2016 by the cross-party Energy and Climate Change Select Committee.

Although the overall 2030 EU target has been agreed by national leaders, the country-by-country division is yet to be determined. This has prompted some to caution against the UK setting an overly ambitious domestic target in the fifth carbon budget. If the UK does more than its fair share, they argue, then others in the EU will do less. They add that this would deliver no additional benefit to the climate, and would damage the UK’s competitiveness.

Both of these arguments have been examined. The impact of carbon budgets on the UK’s competitiveness has recently been studied by LSE’s Grantham Institute. They find, firstly, that existing policies to reduce carbon emissions have not had a negative impact on businesses. Nor do they find evidence of ‘carbon leakage’, whereby carbon intensive industries just relocate to countries with less stringent climate change legislation. Secondly, they show that there are economic benefits for countries that take strong climate action, arguing that the UK in particular is well-placed to take advantage of the global low-carbon transition. This week, the Energy and Climate Intelligence Unit (ECIU) released a report showing that across a range of climate policies the UK is not significantly ahead of its EU competitors. They find in fact that the UK is sixth among the 28 member states, far behind the clear leader Sweden.

The CCC has examined what the likely implications of the EU 2030 target are for the UK. They find that the UK can be expected to be given a target of around 54%, within a range of 51% and 57%. This is compatible with their recommendations for the level of the fifth carbon budget. Internationally, the UK Government has long argued for larger, more developed economies to decarbonise at a faster rate. This is the reason why the UK’s share would in any case be larger than the overall EU target of 40% reduction by 2030 from 1990 levels. Moreover, given the EU and UK share the same 2050 target of reducing their emissions by 80% by 1990 levels, the CCC’s advice on the fifth carbon budget provides the most cost-efficient route to 2050, independent of the interim 2030 target.

The Government championed an ambitious deal in Paris last year, and has repeatedly affirmed its commitment to the Climate Change Act. In the same vein, ministers should agree the fifth carbon budget as soon as possible. Amber Rudd announced in her energy policy reset speech in November 2015 that the Government would set out new policies by the end of 2016 to ensure the UK meets its fourth and fifth carbon budgets. The focus should be quickly turned to establishing these new policies and giving investors a clear direction for future energy policy.

Sam Hall is a Researcher at Bright Blue