What is global warming?
Surrounding the earth is a delicate blanket of gasses that keep the world's climate relatively stable. As the sun's energy flows towards earth, much of it bounces back off the atmosphere; however, the blanket layer captures some of this heat. This is called the greenhouse effect, and serves to sustain life on earth. Without this natural effect, the earth would be uninhabitable, as the earth's temperature would be around -18°C.
However, through deforestation and the burning of fossil fuels (mainly coal, oil and natural gas), humans have changed the makeup of the atmosphere. Since the Industrial Revolution, emissions have steadily increased to a level today that is higher than ever before in human history. By altering the natural balance of gasses, the earth has begun to warm and climate patterns have begun to shift - in many cases intensifying across the globe. This is a serious concern for all life on earth, which will be affected in some way or another by the changes that are implied by this trend.
How are humans involved?
Scientists worldwide have agreed that the earth is warming and human activities are a direct cause; the latest report from the Intergovernmental Panel on Climate Change (IPCC) confirms this evidence. With industrial activities, humans have distorted the natural balance of greenhouse gases in the atmosphere by emitting amounts that alter the earth's climate. Scientists have come to this conclusion based on various findings; computer models which incorporate natural variations – like volcanic activity, orbit changes of the sun – cannot explain the current levels of warming; only human activities serve as the missing link. Also, ice core samples dating back thousands of years show that carbon emissions have never been as high or increased at the speed in which they have within the last few hundred years.
Is not climate change a natural process? Wasn't there an ice age many years ago?
Earth’s climate is always changing to some degree; over the past few million years the planet has experienced ice ages and periods of heat. However, for the estimated 150,000 years of human existence, the climate has been fairly stable, with levels of CO2 always between about 200-300 parts per million:
As this graph shows, humans have always survived in a global climate that has been relatively consistent. Today, CO2 levels are above 380 ppm, higher than ever before in history. If current rates continue, we could have levels between 730 and 1,020 ppm by the end of the century. We are facing an age when earth’s climate could experience some drastic changes.
Around 10,000-20,000 years ago, the earth was colder because it was experiencing a cyclical ice age. This was triggered by a change in the earth’s orbit, which affects the amount of solar radiation reaching the earth; this has been called a Milankovitch cycle. These cycles happen every 50,000 - 100,000 years and have such incremental effect on temperature that they are not relevant when looking at changes within centuries.
What evidence exists that global warming is already taking effect?
Across the globe there are cases that depict the early effects of climate change, demonstrating a sample of what the future could bring.
Evidence of climate change taking effect includes:
- Glaciers worldwide have significantly retreated
- Permafrost that had been stable for thousands of years is now thawing
- Sea level has risen 20cm since 1900
- The intensity of storms has increased, as well as their emergence in new regions of the world
- Animal and plant species are shifting poleward to adapt to the new climate
- Flowering of plants and egg-laying of birds are happening sooner each year due to the earlier spring
Despite the early evidence of these changes, greenhouse gas levels increase faster than the observed shifts occur. This lag time means that we will not see the effects of today’s high emissions until some time in the near future.
Will a few degrees of warmth really matter?
Though it might not seem significant, only a small increase in temperature and minor shift in precipitation patterns could completely alter life as we know it. Because the environment is very delicate, seemingly miniscule changes in climate can wipe out wildlife species, make agricultural land unusable, result in sea level rise, and cause immense shifts in weather patterns that could threaten life on earth. A 3°C increase in global temperature will put more than 1/3 of earth’s species into extinction, significantly deplete agricultural yields across the globe, and put hundreds of millions of people at risk from serious coastal flooding. Within the last 10,000 years, earth’s average temperature hasn’t varied more than 1.0° C; three million years ago, when the temperature was 2-3 degrees higher than today, sea level was 25 meters higher. Seemingly small changes in temperature can make enormous differences to life on earth.
Because the predicted warmth is given in global averages, some areas will experience greater spikes in local temperature and shifts in climate than others. Small average changes also means big changes in the weather extremes; instead of a few degrees warmer weather year round, global warming means that major heat waves and droughts will become common.
How will climate change affect Cambridgeshire and the UK?
The most significant environmental effects of global warming in the UK will be the hotter climate and rise in sea level. Summers will be significantly warmer and drier, with a 60% reduction in rainfall. Wintertime will not be much warmer but will likely face an increase in rainfall, with heavier and more concentrated storms. Along with sea level rise, these storms mean that more flooding will take place, most significantly in low-lying areas like the East of England. Heat waves will likely become the norm by the 2040s. Both droughts and flooding will affect buildings and other infrastructure. Agricultural problems can be expected with erosion and loss of soil fertility.
On a larger scale, global climate change will affect the UK as a member of the global community. Problems will occur due to financial stresses from market losses and disaster relief, displacement of millions of environmental refugees, loss of biodiversity and agricultural shifts, water shortages, and overall challenges in adapting to the wide-scale changes taking place.
What will the effects be around the earth if global warming continues at this rate?
Scientists have come to a pretty firm consensus on the predicted outcomes of global warming. Over the next century, the IPCC predicts global average temperature to increase anywhere from 1.4 - 5.8°C, with more dramatic increases towards the poles (England will face greater temperature changes than Spain). Experts also predict more intense weather across the globe – like droughts in parts of Africa and more severe hurricanes in the Caribbean region. Sea level will continue to rise as glaciers melt and the ocean expands with heat, flooding coastal regions and making some places uninhabitable. Agriculture and water supplies will suffer, while millions of people will be displaced from their homes. It is also likely that diseases that were once limited to certain hot areas will spread throughout the globe.
What can be done to significantly slow down global warming? Is there hope to address this problem?
There is still time to act before major changes to the earth’s climate are irreversible. The IPCC has issued world reports that communicate the severity of this issue and advise governments to act. In 1997, many nations around the world signed the Kyoto Protocol – the first piece of global legislation to address climate change. The UK has become a global leader in the reduction of carbon emissions.
Concrete actions exist to slow global warming. Governments can:
- Increase energy efficiency standards
- Encourage renewable energy sources and consumption
- Discourage dirty energy by eliminating subsidies that promote the use of oil and coal
- Include climate change in education plans
- Protect wildlife and forests which serve as storages of carbon and are threatened by climate change
- Participate in an international agreement which ensures global reduction of emissions
- Drive less and use fuel efficient vehicles
- Keep homes insulated
- Use less electricity
- Purchase local food and goods
- Educate others about the issue
- Vocalise concern about climate change in political arenas
Businesses and non-profit organisations have a role as well. By providing technologies and discovering new ways of doing old things, businesses can lead the way into energy efficiency and away from practices that are contributing to climate change.
What can we do about the changes that will inevitably take place? What is being done about adaption to global warming here in the UK?
Since climate change is already beginning to happen, we must be prepared to deal with effects that we cannot prevent. Addressing the impacts of climate change now will be less costly than waiting for the damage to take place in the future. In the UK, there have already been some plans to address stresses that will likely take place under global warming, relating to floods, development, and availability of information for decision makers. In addition, there is recognition that construction of highways and roads has to take into account future weather changes. On the human side, the Council is making provisions to ensure better protection of those who are vulnerable to heat waves. While the strongest efforts have been in mitigating future climate change, there are things we can all do to adapt to the shifts that will inevitably occur.
Are sudden, catastrophic events like those seen in the recent Hollywood movie, "A Day After Tomorrow" likely to happen?
While scientific predictions are wide-ranging, it is highly unlikely that these types of sudden events will occur. However, certain catastrophic events are possible – some within short time spans. Scientists have pointed to the potential shutdown of the Gulf Stream – the current of warmth brought from the southeast Atlantic to Europe; large-scale, highly destructive hurricanes are likely to replace smaller storms, and sea level rises could inundate much of the populated coastal regions of the world. While the happenings seen in this movie are for entertainment and not education, one must realise that climate change is a serious danger to life on earth; we cannot let Hollywood science distract us from the real threats at hand.