Human impact 

The effect of human activity on the Earth is hotly debated but Dr Rob Bellamy (University of Oxford) says that there are tipping points from which the planet would find it tough to recover.

“Climate change is one of these planetary boundaries, where we’re dangerously teetering on the edge of causing some serious damage,” he says. “There’s the widespread loss of biodiversity and the extinction of various fauna (animals). There’s chemical pollution. There’s ocean acidification.”

Some people are even suggesting that we’re in a new era of the Earth’s history: the Anthropocene. 

“The idea is that the world has reached a point now where humans are having such a massive impact on the world we can consider this as being a new epoch (a new geological age of the Earth),” he says. 

Switching off lights that aren’t needed, using public transport instead of driving, recycling our rubbish … most of us know about the environmentally-friendly things we could be doing each day.

But how necessary is it for us to be saving the planet’s resources, and how serious are the effects of climate change?

To refresh your knowledge of the science behind climate change and the Greenhouse effect, take a look at the video below, which compares the process to a big game of Tetris!   

https://www.youtube.com/watch?v=ztWHqUFJRTs

Technology to the rescue..?

Dr Rob Bellamy works in the Institute for Science, Innovation and Society (InSIS) at the University of Oxford, and specialises in research projects about climate change and potential solutions. He explains that there have been two main approaches to dealing with the problems of climate change: 

•    adaptation -  dealing with its effects. 
•    mitigation - dealing with its causes.

He adds that there is now a third approach which consists of radical ideas about ways in which climate change could be controlled. For example, some have suggested putting a mirror into orbit around the Earth, reflecting sunlight back into the atmosphere, like a big sunshade.

This concept of intervening in the climate is called geoengineering. And since the 2015 Paris Agreement, when governments agreed that they would aim for limiting the rise in global temperatures to 1.5°C above pre-industrial levels, it seems more and more likely that such technology will be used. 

“So much of the concern really is rising from the fact that scientists and policymakers are realising that we’re not actually going to be able to avoid dangerous climate change through mitigation,” says Dr Bellamy. “We’ve had quite a long time already of trying to reduce our CO2 emissions, but they keep going up, and this geoengineering idea is the deliberate large-scale intervention in the Earth’s climate system - it’s basically a technological fix.”

There are two types of geoengineering. The first is greenhouse gas removal: removing and storing carbon dioxide and other greenhouse gases from the atmosphere. The second is solar radiation management, reflecting a level of sunlight away from the Earth, but not actually doing anything to deal with greenhouse gas emissions in the first place.

Making change happen

There’s plenty that governments can do to help protect the environment, making laws that work well in their own countries, but actually getting this done is a slow process.

“Unfortunately what has been proposed so far falls quite dramatically short of what we would need,” explains Dr Bellamy. “It’s this massive gap between what’s been pledged in terms of emission reductions and the ambitions in the Paris agreement that leads people to start thinking about geoengineering.”

He adds that all the plans for the future that see the Paris agreement targets being met require the use of technologies that haven’t been invented or invested in yet.

So can individuals really make a difference? 

Yes, they can - explains Dr Bellamy - but often you’re preaching to the converted. The biggest challenge is to convince others who don’t think in the same way to you.

Unfortunately, there’s not a great deal of agreement when it comes to managing the problems of climate change across the world. This is simply because people have different interpretations of how stable the climate is and different preferences for how climate change should be solved.

Dr Bellamy says that humans are ruining the Earth and we need to reduce our footprint but humans are also improving the Earth for human benefit. We can adapt to some of the negative side effects of this and we are capable of managing the Earth in balance. 

With so many different viewpoints, it’s no wonder that there’s no agreement on what to do next.

“There’s a great quote by political commentator Walter Lippmann, who said that the “the goal of politics is not to get people to think alike. The goal of politics is to get people who think differently to act alike”, says Dr Bellamy. 

So what do you think? 

Our oceans cover around 70% of the Earth’s surface, yet there’s still lots to discover about the life they support and their fragile eco-systems. In fact, we have better maps of other planets like Mars than we do of our seabed, which remains 95% unexplored. Researchers at the Nekton Oxford Deep Ocean Research Institute have been working to find out how our oceans function and how healthy they are. Principle Scientist at Nekton, Dr Lucy Woodall explains that when trying to understand our relationship with the oceans it’s important to start by asking what do our oceans do for us? 

Oh, I do love to live by the seaside…

Everyone, even those who don’t live anywhere near the coast, is affected by the activities of our oceans. This is because its algae produce 50% of the Oxygen we breathe and absorbs large quantities of carbon dioxide, ensuring that our air is chemically balanced. The fish found within them also provide the largest source of protein in many diets across the world. And the seas control our climate and weather. 

More than this, the ocean holds social and cultural value to many of us too. The seas are used in the transportation of goods, and they play an important role in the travel and tourism industry…just think about the continued popularity of cruises and seaside holiday resorts.
 

So how are we treating them? 

Well, this is a big question in itself. Through the ongoing process of man-made climate change, largely linked to the burning of fossil fuels and ongoing deforestation, our oceans are being significantly affected by human activity. An increase in sea temperature has led to large areas of coral bleaching in the sun. This happens when the tiny algae that make up the large mix of colours seen on coral are ejected (as in the picture below). As a result, the coral is left without its key source of food and energy and is at risk of disease. 

Coral bleaching at Heron Island, February 2016. Credit: The Ocean Agency / XL Catlin Seaview Survey / Richard Vevers CC-BY 2.0 

Likewise, ocean acidification due to increased levels of carbon dioxide in seawater has also contributed to coral bleaching. This occurs when some of the greenhouse gases released into our atmosphere are absorbed by the oceans and form a mild acid when dissolved in water. A growing concern is that this increase in acidity, which in turn means less calcium carbonate available in the water, can make it harder for coral and some plankton species to create their shells or plates. Ongoing research is taking place but it's believed that coral bleaching and ocean acidification may pose threats to species who live and breed among coral reefs, and namely, microscopic plankton which form a vital basis to most marine food chains. 

Another area researchers are taking a look into is large-scale deoxygenation i.e. reduced oxygen levels in the ocean. It's not entirely clear what's responsible for this shift but it's thought to be mostly due to changes in ocean circulation. In other words, it could be a result of less oxygen-rich water coming from the surface ocean which could be linked to the Greenhouse Effect and ongoing processes of climate change.  

Plus, our sea levels are rising. This is due to two factors: thermal expansion (water warming up and expanding) and melting ice sheets. This has started to affect animal populations - placing those living in the Poles and along our coastlines most at risk. 

Intensive fishing is another issue our oceans face. Modern technological advances and increasing demand for food mean that seas are being fished continually and at greater depths - not giving fish populations the time to replenish. Sea mining and drilling for precious metals, which are used in electronic items like smartphones, can also disrupt ocean life and damage the seabed. 

Research has shown that pollution is damaging sea life even further. This stems from the chemicals offloaded from ships, inland fertilizers and untreated sewage which leak into our waterways, and even sunscreens that wash off swimmers on the beach. Not to forget a large amount of plastic waste inappropriately disposed of that is then swept away by the sea. Dr Lucy Woodall explains that many plastics break down into a ‘soup’ of smaller pieces (similar to the size of your small fingernail)and can be ingested (eaten) by a wide range of wildlife. 

Photo C/O AD Rogers from JC66 cruise funded by NERC and the IUCN Seamounts project.

But what about the natural changes our planet is going through?

So let’s revisit our Big Question…what does it really mean to ‘ruin’ the planet? After all, the Earth has always undergone large natural variations and even abrupt shifts in which humans played no part at all (often because we didn’t exist yet!) 

These natural changes are caused by a combination of external and internal factors to the Earth’s climate system. External factors (also known as ‘external forcing’) can include variations in the Earth’s orbit around the sun and any changes in the amount of radiation coming from the sun. While internal factors (commonly known as ‘internal variability') can refer to the after-effects of large-scale volcanic eruptions, natural changes in the make-up of our atmosphere and variations in the way our oceans operate. 

And so in light of all this...

How can we work out whether human impact measures up against ongoing natural changes?

To start with, we need to work out what these natural changes look like. Paleoclimatologists gain this knowledge by reconstructing the climate of the past from modern-day records. These records might come from air trapped in the ice over Antarctica or Greenland, stalagmites from ancient caves, or the remains of ancient coral reefs. From these, researchers can determine how different parameters of the climate, such as temperature, sea level and rainfall have varied in the past. 

Equipped with this information, we can then ask whether recent changes are extraordinary in comparison. For example, records show that atmospheric temperatures have been increasing steadily since the end of the last ice age - around 20,000 years ago. However, since the 1950s, they have been increasing at a faster rate. This suggests that something has changed in the Earth system.

Even if we convince ourselves that recent changes are extraordinary, we still have some work to do before deciding that they’re a result of human activity. Since scientists have to try and establish which of the many possible contributors (both natural and human-induced) best explain these extraordinary changes. In the 'recent' case of the increased rate of atmospheric temperature rising, possible explanations include (amongst many others): 

•    more intense solar radiation (external forcing) 
•    higher levels of carbon dioxide in the atmosphere (almost entirely due to human activity)
•    a decrease in the amount of heat stored in the ocean (internal variability)

In this instance, scientists have found that the increase in atmospheric carbon dioxide explains the large majority of the recent change. And so we can conclude that human activities are affecting at least this aspect of the Earth system in a way that goes beyond natural variability.

But what about other trends such as the rise in our sea levels… is this extraordinary, and if so, is it due to human activity, natural variability or a mix of the two? 

This is a tricky subject...Whatever your thoughts are on our Big Question, it’s important to consider all sides of the argument and the different factors at play (both natural and man-made). After all, it’s never that straightforward when it comes to Mother Nature…