Oxford researchers speak to people all over the world on issues of climate science. Here, a handful of our climate scientists answer some of the questions they hear most often.

Q. What is climate change?

Climate change is a large-scale, long-term shift in the planet’s weather patterns and average temperatures. These changes have always happened and will continue to happen; they're what we call 'natural variation'. Recently, the term climate change has begun to be used for the way that humans have had an effect on the planet’s climate, in addition to any natural changes that might happen.

There are several good web sites which explain the basic science of climate change, as well the causes and the impacts of climate change:

Q. Is the climate really changing?

Answer by Tina Fawcett, Environmental Change Institute:
Yes, the climate is really changing, and this is due to human actions. The United Nations' scientific advisors noted a 2014 report: "Human influence on the climate system is clear, and recent anthropogenic (human-caused) emissions of greenhouse gases are the highest in history. Recent climate changes have had widespread impacts on human and natural systems."

Q. How do I persuade somebody it isn’t El Niño which is causing climate change?

Answer by James King, School of Geography:
El Niño refers to natural warming of the tropical Pacific Ocean. It's part of a cycle called the El Niño Southern Oscillation (ENSO) which has been happening for thousands of years and which also includes La Niña, which results in cooling of the tropical Pacific. On average, El Niño tends to cause warmer temperatures and La Niña tends to cause cooler temperatures.

ENSO is one of the most important features of Earth’s climate and affects weather patterns around the world, but it is not the cause of global warming. This is shown by the fact that if you remove the effects caused by ENSO from recent temperature records, global warming is still there. The ENSO cycle is an example of what scientists call 'internal variability' – over periods of a few years ENSO does affect temperature, but the amount of warming and cooling brought by El Niño and La Niña evens out because both are just moving heat energy around – no heat energy is added to the climate system by internal factors. That would be like arguing that the water in a bath heats itself, rather than being warmed by an external heat source (a boiler). Climate change is likely to affect the ENSO system and change its impacts across the world, but exactly how is still a question scientists are trying to answer.

For a more comprehensive description you can read the Met Office's overview of El Niño, La Niña and the Southern Oscillation.

Q. When will climate change be stopped?

Answer by Tina Fawcett, Environmental Change Institute:
This question was asked by a young child. I found it very moving. I don't have a good answer – it would be easy to say the climate is always changing – but I think questioner meant 'when will the climate go back to how it was before human activities changed it?' I’m not sure it ever will.

Q. How quickly would the earth recover if we stopped emitting all greenhouse gases today?

Answer by James King, School of Geography:
Humans have been putting greenhouse gases into the atmosphere and warming the planet for over 100 years now. Because those gases stay there for a long time, climate change would continue even if we stopped all greenhouse gas emissions today; the gases we have already emitted would still be there causing the climate to change. If we stopped now, the Earth would most likely continue to warm for another 40 or so years before reaching a stable point about 0.6°C warmer than average. To keep warming to below 1.5°C below average (an ambitious target of the Paris Agreement), we would need to stop emitting by the middle of the 21st century.

If you'd like to read more there is Professor of Climate and Space Science, Richard Rood's answer to this question on The Conversation.

Q. How fast is climate change going to happen?

Answer by James King, School of Geography:
Climate change is already happening, and fast – the last 5 years were the 5 hottest years on record around the world, and Arctic sea ice reached its lowest recorded point in 2012. Since the late 1970s the rate of global warming increased significantly, and is currently between 0.15-0.2°C per decade. At this rate of warming, we could pass 1.5°C by 2030, when our aim is to keep temperatures below that by 2100.

Other resources on this topic include the IPCC summary for policy makers and an animation of global temperature anomalies over the last 120 years on the NASA Earth Observatory website.

Q. If the absorptive potential of CO2 doesn’t change with increased concentration, why does it cause the planet to heat up?

Answer by James King, School of Geography:
Carbon dioxide (CO2) is the most abundant greenhouse gas. It warms the atmosphere by absorbing heat from Earth’s surface and preventing it from escaping into space (the greenhouse effect). While it is true that increasing the concentration of CO2 in the atmosphere doesn’t change its chemical properties, including what wavelengths it absorbs, it does increase the range of wavelengths absorbed. Therefore, the planet heats up because the CO2 can trap more heat in the atmosphere if it is at a greater concentration.

Contributions to climate change

Answer by Monica Zurek, ECI

Q. Do you do anything to support or research veganism?

A number of projects at ECI research changes in consumer behaviour around meat eating. A good resource on the discussion on food and climate change is the Food and Climate Research Network (FCRN) and its Food Source section. 

The university is involved in a number of projects that work on meat eating behaviour:

Q. What is the contribution of methane and animal food production to climate change? 

Currently it is estimated that livestock contributes 14.5% of human-made greenhouse gas emissions. Carbon sequestration has been posited by pro-livestock stakeholders to offset these emissions, but the evidence is that this potential is limited, and very dependent on circumstance (see www.foodsource.org.uk). In terms of overall contributions of the food system to greenhouse gas emissions, it is estimated that between 25-30% are related to the way how we feed ourselves – so this includes transporting, storing, preparing and cooking food, as well as growing it.


Q. FutureLearn has a few climate related courses (free!) but needs more. Can you make a free online climate science course?

Researchers at the Environmental Change Institute are planning to make more climate related material for the general public available on the web, although not as a FutureLearn course. It should be available soon. 

In the meantime – you might like to have a look at our Climateprediction.net site – the world’s largest climate modelling experiment for the 21st century.

Q. Are there climate modules for school children KS1 / 2 / 3 / 4?

Answer by Heather Waller, ECI:
A variety of organisations offer some climate teaching resources for children of various ages, and information aimed directly at children and young people. Please note, we have not read all the material on these websites – so can't guarantee how accurate or useful it is.

Q. What subjects should my daughter study to be a climate scientist?

Answer by Tina Fawcett, Environmental Change Institute:
The most relevant subjects are physics, maths and geography. However, many of our climate scientists didn't study all of these for their A levels, and have learnt what they need at university or through workplace training.

Answer by James King, School of Geography:
Climate change is the biggest problem we face, and everyone has something to contribute to it. As well as understanding the science, we need to understand how people can respond and act, and how to communicate the problem better. No matter what subjects you do at school, if you're interested in climate change, you'll find something to say about it through the lens of those subjects. Not everyone studying climate change is a scientist!

About Oxford University

Q. Can I join the Oxford Climate Network?

The Oxford Climate Research Network is an internal network of more than 170 Oxford University scientists focused on the challenge of managing climate change in a complex and uncertain world.

A short film introduces the network:

The network is for senior Oxford researchers and academics only, and isn't open to those outside the research community. However, there are many talks at Oxford about climate and other environmental issues, most of which are open to the public. Please see the event listings on the ONE Network pages for up to date information.

Q. What green student initiatives are there at Oxford University?

Answer by Ian Curtis, Environmental Change Institute:
In March 2019 Oxford students were clearing plastic garbage from Aldabra Atoll in the Indian Ocean, home to the world's largest group of giant tortoises. Just one of many initiatives for dark blue students keen on being green – from joining the world’s largest climate modelling experiment, going veggie in November to teaching local school pupils.

Many initiatives are student-led but others are organised by, for example, the Environmental Change Institute and the Environmental Sustainability Team at Estate Services. Some are very new but others are "ancient" – like the Exploration Club founded in 1927!