The ocean is absorbing large amounts of anthropogenic heat and carbon. This is altering many ocean properties, which will influence the viability and health of marine biota. At the base of the foodchain are phytoplankton, the primary producers, which not only support the marine ecosystem but sequester carbon to the deep ocean. In this web focus we present a variety of original research and opinion pieces that highlight the pressures on marine phytoplankton under climate change and suggest directions for future research.

In June 2015, the Pope delivered a high-profile encyclical on climate change and the environment. The near-200 page document called for the Catholic church to enter a "dialogue with all people about our common home". This Focus provides a scholarly foundation for that dialogue, with world-leading ecologists, sociologists and economists highlighting the strengths and limitations of the Pope’s call for action.

The El Niño/Southern Oscillation (ENSO) is a natural climate phenomenon that has worldwide impacts. It alternates between two phases – the warm phase (El Niño) and the cold phase (La Niña) – that result from changes in the sea surface temperature and associated atmospheric circulation. This influences the hydrological cycle and global weather through teleconnections. In this web focus, we present a variety of original research, opinion and review pieces that highlight our current understanding of how climate change is affecting ENSO.

Today Africa faces a multitude of development and sustainability challenges. Climate change is expected to exacerbate these challenges through its direct effects on people and the environment, as well as by imposing the need for measures to keep greenhouse gas emissions low and adapt to climate impacts. However, there remains a dearth of information with which to understand the nature of these risks for Africa and how best to tackle them. In this Insight we highlight some of the key ways that climate change might impact African wildlife and farming systems, and the interacting pressures on water, energy and food resources. The effects of air pollution on African climate are also considered, as is the uptake of available climate information by decision makers.

An emerging body of literature is exploring the role of the media in reporting climate change science and the recent IPCC efforts to reach out policymakers and the public. In this focus, Nature Climate Changepresents an Article examining media coverage of the IPCC Fifth Assessment Report – in broadcast, print and social media – and a series of opinion pieces looking at the effectiveness of the IPCC communication strategy and the ways experts study media power in the context of climate change.

The countdown is on to reach a legally binding agreement between all nations on actions to mitigate climate change. In 2011, the United Nations Climate Change Conference agreed that such a deal will be in place by 2015, and implemented by 2020. In this joint web Focus, timed to coincide with the New York Climate Summit, Nature GeoscienceandNature Climate Changepresent a series of overview articles and opinion pieces that take stock of emissions and climate change uncertainties and discuss potential ways forward.

The countdown is on to reach a legally binding agreement between all nations on actions to mitigate climate change. In 2011, the United Nations Climate Change Conference agreed that such a deal will be in place by 2015, and implemented by 2020. In this joint web Focus, timed to coincide with the New York Climate Summit, Nature GeoscienceandNature Climate Changepresent a series of overview articles and opinion pieces that take stock of emissions and climate change uncertainties and discuss potential ways forward.

Climate change fundamentally alters the way that farmers need to plan and manage their operations. This is necessary to avoid the worst impacts of climate change while reducing greenhouse gas emissions and meeting growing demand for food, fuel and fibre. This is a grand challenge for farmers and has the potential to touch the lives of everyone that uses farmed produce; in short, all of us. In this focus, Nature Climate Changepresents a variety of original research and opinion pieces that highlight important themes in our understanding of the effects of climate change on agriculture, agriculture's influence on the climate and our capacity to adapt to better face these challenges.

Growing population and increasing demand for higher living standards have led to the overuse of water resources. More recently, the management of watersheds has been threatened by the impacts of climate change on the water cycle. In the face of these challenges, water companies and agribusinesses need to seek solutions. In this focus, Nature Climate Changepresents four opinion pieces that discuss the risks and opportunities posed to private companies by water scarcity, highlight the steps some companies have already taken and, overall, the actions still required.

From the industrial revolution onwards, greenhouse gas emissions resulting from human activities such as the burning of fossil fuel and changes in land use have caused the planet to warm. However, since 1998 – a year of record warmth – the rate of warming has been lower than in the late twentieth century. In this joint web focus, Nature Climate ChangeandNature Geosciencepresent original research and opinion pieces that discuss the causes of the slowdown in surface warming and examine how the science has been communicated by researchers and the media.

The hydrological cycle influences the development of societies, as well as human lifestyles and well-being across the globe. How climate change might affect the timing and variability of precipitation, along with the resulting floods and droughts, could significantly impact agriculture, water resources and natural ecosystems. In this web focus we present a variety of articles, including original research, that highlight trends in precipitation and flooding under climate change.