Preface to the fourth edition

Climate change is one of the four defining challenges of the 21st century, along with environmental degradation, global inequality, and global insecurity. Climate change will continue to increase the temperature of the Earth and raise global sea level. It will increase the frequency of extreme weather events such as droughts, heat waves, floods, and storms threatening the health and livelihoods of billions of people. The severity of these climate change impacts will depend on what we do now to cut greenhouse gas emissions.

In the past thirty years, the amount of carbon dioxide emitted through human activity has doubled. This represents a collective failure of the world’s leaders to focus on the climate crisis. Despite 2020 and 2021 being dominated by the Covid-19 pandemic, the geopolitical landscape around climate change has shifted seismically (Figure 1). In June 2019, the UK parliament amended the 2008 Climate Change Act to requiring that the government reduce the UK’s emissions of greenhouse gases to net zero by 2050. In 2021 the UK announced an interim target of a 78% cut in carbon emissions by 2030. The European Commission announced that the EU would reduce its greenhouse gas emissions by at least 55% from 1990 levels by 2030, instead of the 40% cut agreed six years ago. This is a major step towards the EU’s overarching pledge of carbon neutrality by 2050. In September 2020, China’s President Xi Jinping announced via video-link to the UN General Assembly in New York that the country would aim to reach peak emissions before 2030, followed by a long-term target to become carbon neutral by 2060. China is the world’s largest carbon emitter, accountable for around 28% of global emissions, and up to now has not committed to a long-term emissions goal.

1. Flattening the curve: comparing Covid-19 and climate change.

In 2021, the USA, the second largest emitter with around 15% of global emissions, has re-engaged with the climate negotiations. President Trump in 2020 took the USA out of the 2015 Paris Agreement. President Biden has re-engaged The USA in the Paris Agreement and has become a strong advocate of collective international action to deal with climate change. In 2021 the US announced a target cut of 50% of its carbon emissions by 2030 and pledged to reach net carbon zero by 2050. President Biden has also reinstated the environmental regulations removed by President Trump, put in major policies to cut greenhouse gas emissions and greatly increased federal funding for renewable energy and the US green economy. For the first time in over a decade there is now hope that the nations of the world can cut greenhouse gas emissions significantly and start the journey to a cleaner, greener, safer, healthier, and more sustainable world.