Climate emergency

There is a climate and ecological emergency, caused by humans – all of us but some more than others – often without realising our impact. These problems are affecting our planet and our communities already, and are predicted to get much worse unless we rapidly take action. This page provides further detail on the climate emergency, building on the shorter summary given by the Climate and ecological emergency page.

Climate change is being caused by the emission of carbon dioxide (CO₂) and other greenhouse gases (such as methane (CH₄)) by humans at a much faster rate than they are naturally emitted, largely through the use of fossil fuels, but also through land use choices. Greenhouse gases have increased in the atmosphere, acting like a greenhouse; solar energy enters the atmosphere and warms up the planet, but the additional greenhouse gases are increasingly blocking the heat energy from escaping. The IPCC comprise a large group of leading climate scientists who have collectively demonstrated beyond reasonable doubt that climate change is caused by humans. Their Global Warming of 1.5°C report demonstrates that we need to limit global warming to 1.5°C to avoid the worst effects of climate change. In August 2021, the IPCC press release to their AR6 Climate Change 2021:The Physical Science Basis report outlined how “unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions, limiting warming to close to 1.5°C or even 2°C will be beyond reach” i.e. immediate and transformative global action is required. IPCC’s AR6 Climate Change 2022: Impacts, Adaptation and Vulnerability report (February 2022) stated that “Human-induced climate change, including more frequent and intense extreme events, has caused widespread adverse impacts and related losses and damages to nature and people, beyond natural climate variability” and “The rise in weather and climate extremes has led to some irreversible impacts as natural and human systems are pushed beyond their ability to adapt.” It also reports that “Approximately 3.3 to 3.6 billion people live in contexts that are highly vulnerable to climate change.” The sooner we act, the smaller the impacts will be.

Climate change is predicted to impact all areas globally, to a greater or lesser extent. We are already observing many impacts. These include (but are not limited to):

• Increased average temperatures of land, air and oceans – causing increased risk of heat waves, droughts and fires
• Increased frequency and intensity of extreme weather events such as storms – with resulting disruption and damage
• Melting of ice and sea level rise – causing increasing flood risk to coastal settlements with resulting disruption and damage
• Increased habitat changes and species extinctions (see the ecological crisis section below for further impacts)

For further information on these and other climate change impacts along with the current scientific basis for climate change and the required climate action, read the IPCC’s AR6 Climate Change 2021:The Physical Science Basis and AR6 Climate Change 2022: Impacts, Adaptation and Vulnerability reports.

There are already many deaths are caused by climate change. As reported by Grist, a study by Vicedo-Cabrera et al. (2021) suggested that around 100,000 people per year are currently killed by heat who would not have died if climate change was not happening. It is likely this is an underestimate due to lack of data in the places that are worst affected by extreme heat. Meanwhile, Bloomberg reports another study from 2021 which suggests almost 10% of global deaths, around 5million per year, are linked to climate change. In 2018, the World Health Organisation estimated that between 2030 and 2050, climate change is expected to cause approximately 250,000 additional human deaths per year (i.e. 5 million over 20 years), from malnutrition, malaria, diarrhoea and heat stress alone. However, this does not include deaths from physical risks such as from increased storms, flooding and fires, and it considers relatively short term climate change impacts which are less severe than the longer term climate change impacts will be; this could be considered as a conservative lower estimate, with a potential upper estimate being many times higher over the short term and human extinction in the longer term (see the Ecological crisis section).

The worst affected areas are expected to be those that have contributed least to climate change and that are less able to cope with the impacts e.g. Africa. Climate change is expected to increase inequality. Climate justice and social equity are therefore key themes to consider when trying to address climate change, in which we must seek to ensure that no-one is left behind and that the benefits of taking climate action are shared. See the Climate justice page for further detail on this.

Current climate action is targeted at limiting global warming to 2°C and is insufficient even to achieve that aim. IPCC’s AR6 Climate Change 2022: Mitigation of Climate Change report confirms that:

• without a strengthening of policies beyond those that are implemented by the end of 2020, greenhouse gas emissions are projected to rise beyond 2025, leading to a warming of 3.2°C.
• to limit warming to 1.5°C or even 2°C, rapid, deep and in most cases immediate greenhouse gas emission reductions are required in all sectors.

Many hope that the series of annual COP summits will generate the high level global commitments and agreements required to promote action to limit global warming to 1.5°C and avoid the worst effects of climate change. Despite minor progress over time, politicians and nation states currently categorically fail to propose actions at anywhere near the scale or speed needed to address the Climate and ecological emergency. None of the large nations with significant impact and influence have yet even proposed to ‘do their bit’ at home sufficiently, so it is no surprise that the overall agreement to date is disappointingly weak. However, by supporting and progressing grassroots community and individual action (see the Climate and ecological emergency page), together we can go a long way towards making up for the failings of our politicians. It is important to note that high level political commitments do not in themselves mean that anything changes. It is the implementation of underlying Government policies and specific actions by organisations and individuals that matters, and organisations and individuals can do this voluntarily. Appropriate government policies could certainly make it easier for organisations and individuals to do the right thing.

Watch this video from Climate Adam which outlines some of the principles behind climate targets and considers whether achieving net zero carbon by 2050 is enough to limit global warming to 1.5°C.

The earth climate system is complex and difficult to predict. It has a natural momentum and an inbuilt time-lag which means that even if we stop all greenhouse gas emissions immediately, there will be further warming in years to come.

The system also includes components that can provide strong positive feedbacks under certain conditions. For instance, global warming is melting the Siberian permafrost and large volumes of methane gas are being released which goes on to contribute to even more warming. Such occurrences may start to happen at a certain “threshold” level of global warming (e.g. when it is warm enough in Siberian summers for the permafrost to melt) and then accelerate the warming further. It is challenging to predict exactly when such feedbacks will occur and how much additional warming they will trigger. The more global warming that occurs, the higher the risk that such positive feedbacks may change the dynamics of the warming away from current predictions and towards a faster run-away trend, with much worse impacts. Such risk are considered relatively low currently if we follow the scientific guidance to address climate change; however, unpredictable factors are a powerful reason to ensure that we do follow this urgently.

The IPCC have outlined the global decarbonisation pathways that are required to limit global warming to 1.5°C:

These pathways are based on the concept of a remaining CO₂ budget that we are able to emit and a % probability that the action assumed to be taken will achieve the aim. The graph represents several scenarios and approaches that could be taken to achieve the aim. In all scenarios assessed we need to take significant action to reduce our emissions before 2030, unless we are prepared to overshoot and then have to do much more later on (i.e. go far beyond zero carbon and rely on carbon removal, which is unproven to be achievable on such a scale). The different pathway lines cross over in the middle and then spread out, demonstrating that the quicker we start acting, the less we need to do overall and that even small delays now will make it much more challenging to succeed. The total CO₂ emissions over the period is what matters, and acting quickly rather than slowly makes a huge difference to this total.

It should noted that such modelling is based on % probabilities of achieving the aim, which are typically set at 50-66%; therefore even if we take such action, there would be a 34-50% chance that it will be insufficient to limit warming to 1.5°C – still a rather large and uncomfortable risk to be taking. Furthermore, there is a large uncertainty over the exact size of the remaining carbon budget, although it may be up to about 15 years worth of emissions at the current global rate. Read this Carbon Brief article for further detail and commentary on this.

The main implication of these points including our current trajectory and the related uncertainty is that we would be wise to adopt the precautionary principle and limit the risk of bad consequences by acting faster than the modelling assumes. Therefore, we suggest considering such figures as a critical baseline target not to exceed, but aiming to be well ahead of this where possible.

An illustration of how much global CO₂ emissions need to reduce by 2030 was provided by the World Resources Institute in 2019, which further emphasises the critical need for large and fast reductions:

Greenhouse gas levels, global warming targets and the impact of activities are usually framed in terms of equivalent CO₂ emissions (CO_2eq ). This includes the combined impact of CO₂ and other greenhouse gases including methane (CH₄), nitrous oxide (NO2), and synthetic gases such as hydroflourocarbons (HFCs), each of which has a different Global Warming Potential (GWP). The contribution of a molecule of CO₂ to global warming is defined as the basis of GWP for other gases, so CO₂ has a GWP of 1. Overall CO₂ is the most impactful greenhouse gas considering the number of molecules of gas in the atmosphere and the GWP per molecule. There are far lower numbers of molecules of the other greenhouse gases, which are relatively less important overall, although each molecule may have a much higher GWP, up to tens of thousands in some cases. Earth’s atmosphere is a dynamic system and greenhouse gases have a varying average residence time in the atmosphere until they are converted to another form within the earth system or lost to space. Methane, for instance has a shorter residence time than CO₂ , so although it is important to include for when thinking about addressing global warming in coming decades, it is expected to be less significant over hundreds of years.

It should also be noted that overall water vapour actually makes the biggest contribution to global warming of all gases, however, this simply amplifies any warming produced by other greenhouse gases rather than driving global warming. Increased greenhouse gases in the atmosphere increase the air temperature, which allows air to hold more water vapour, which further warms the air.

For information on the interlinked ecological crisis, other linked crises and solutions at high level (for Governments) and grassroots level (for individuals) see the Climate and ecological emergency page.