ความเห็นเพิ่มเติมที่ 871 1 ม.ค. 2554 (11:13)
CLIMATE CHANGES WEATHER VANE
Millions of us tune into TV channels everyday to find out what the weather has in store for us. A network of European weather presenters is tapping into the public trust associated with their profession and using their reach with viewers to raise awareness of climate change.
The key difference between weather and climate is one of time, with weather covering short periods and climate covering long ones. The close relationship between the two means that meteorologists are well placed to forward the debate on climate change and that is exactly what is happening.
Weather presenters across Europe have been using their high public profiles and credibility to raise awareness of one of the greatest challenges facing our world today. One example is Jill Peeters, a weather presenter at VTM, a commercial television channel in Flanders in Belgium. As well as keeping viewers posted on when they can expect a break in the clouds and some sunny spells in notoriously wet Belgium, she has also made a name for herself as a climate change campaigner.
Peeters has also published a popular book, Ons planet wordt heet (Our planet is getting hot), writes regular articles on global warming for the Flemish press and has produced climate-related documentaries.
Peeters book enjoyed a warm reception. When my book was released, it was among the top 10 bestsellers in Flanders. That's not bad at all for a book about such a complicated scientific subject. And the reactions are still very positive, she explains.
The Flemish weather presenter has also drawn attention to the lesser-known consequences of climate change. She produced a documentary about the El Molo people who fish Lake Turkana in Kenya. As the lakes waters recede, due to global warming and damming, their survival is under threat.
It was amazing how many people were touched by this story. The documentary brought global warming into their living rooms, she recalls. Im convinced that only this kind of personal story can change peoples minds.
CLIMATE ACTION NOW
Two large ice blocks captured the public's attention at the United Nations climate change conference in Poznan, Poland. The European Commission's exhibition was designed to show the effects of climate change on our planet.
With the conference talks providing a crucial step in ongoing negotiations to reach a future international agreement to fight climate change, the exhibition aimed to underline the urgent need for action. The message was clear: our choices on energy and technology today will determine the future of our planet.
The ice blocks symbolised the consequences of climate change and higher global temperatures, including melting polar ice caps and rising sea levels. The exhibition presented two blocks of ice melting at different rates.
The first cube, with the EU logo inside, melted much more slowly than the second cube. It represented a situation in which EU proposals on greenhouse gas emissions reductions and energy savings had been implemented. Although water levels rose, they did not reach dangerous levels.
The second cube that melted more quickly illustrated the catastrophic consequences of taking no action against climate change.
Polish members of the Climate Broadcasters Network-Europe Marek Horczyczak, Jarosław Kret and Tomasz Zubilewicz presented special weather forecasts next to the ice cubes exhibition on 1 and 2 December, during which they explained the impacts of climate change and gave tips to the public on how to reduce greenhouse gas emissions and save energy in daily life. These weather forecasts, which were broadcast by the Polish channels TVP1, Polsat News, TVN Meteo and TVN24 had an audience of over 8 million people.
Glaciers are melting, sea levels are rising, cloud forests are drying, and wildlife is scrambling to keep pace. It's becoming clear that humans have caused most of the past century's warming by releasing heat-trapping gases as we power our modern lives. Called greenhouse gases, their levels are higher now than in the last 650,000 years.
We call the result global warming, but it is causing a set of changes to the Earth's climate, or long-term weather patterns, that varies from place to place. As the Earth spins each day, the new heat swirls with it, picking up moisture over the oceans, rising here, settling there. It's changing the rhythms of climate that all living things have come to rely upon.
What will we do to slow this warming? How will we cope with the changes we've already set into motion? While we struggle to figure it all out, the face of the Earth as we know itcoasts, forests, farms and snow-capped mountainshangs in the balance.
The "greenhouse effect" is the warming that happens when certain gases in Earth's atmosphere trap heat. These gases let in light but keep heat from escaping, like the glass walls of a greenhouse.
First, sunlight shines onto the Earth's surface, where it is absorbed and then radiates back into the atmosphere as heat. In the atmosphere, greenhouse gases trap some of this heat, and the rest escapes into space. The more greenhouse gases are in the atmosphere, the more heat gets trapped.
Scientists have known about the greenhouse effect since 1824, when Joseph Fourier calculated that the Earth would be much colder if it had no atmosphere. This greenhouse effect is what keeps the Earth's climate livable. Without it, the Earth's surface would be an average of about 60 degrees Fahrenheit cooler. In 1895, the Swedish chemist Svante Arrhenius discovered that humans could enhance the greenhouse effect by making carbon dioxide, a greenhouse gas. He kicked off 100 years of climate research that has given us a sophisticated understanding of global warming.
Levels of greenhouse gases (GHGs) have gone up and down over the Earth's history, but they have been fairly constant for the past few thousand years. Global average temperatures have stayed fairly constant over that time as well, until recently. Through the burning of fossil fuels and other GHG emissions, humans are enhancing the greenhouse effect and warming Earth.
Scientists often use the term "climate change" instead of global warming. This is because as the Earth's average temperature climbs, winds and ocean currents move heat around the globe in ways that can cool some areas, warm others, and change the amount of rain and snow falling. As a result, the climate changes differently in different areas.
Aren't temperature changes natural?
The average global temperature and concentrations of carbon dioxide (one of the major greenhouse gases) have fluctuated on a cycle of hundreds of thousands of years as the Earth's position relative to the sun has varied. As a result, ice ages have come and gone.
However, for thousands of years now, emissions of GHGs to the atmosphere have been balanced out by GHGs that are naturally absorbed. As a result, GHG concentrations and temperature have been fairly stable. This stability has allowed human civilization to develop within a consistent climate.
Occasionally, other factors briefly influence global temperatures. Volcanic eruptions, for example, emit particles that temporarily cool the Earth's surface. But these have no lasting effect beyond a few years. Other cycles, such as El Niño, also work on fairly short and predictable cycles.
Now, humans have increased the amount of carbon dioxide in the atmosphere by more than a third since the industrial revolution. Changes this large have historically taken thousands of years, but are now happening over the course of decades.
Why is this a concern?
The rapid rise in greenhouse gases is a problem because it is changing the climate faster than some living things may be able to adapt. Also, a new and more unpredictable climate poses unique challenges to all life.
Historically, Earth's climate has regularly shifted back and forth between temperatures like those we see today and temperatures cold enough that large sheets of ice covered much of North America and Europe. The difference between average global temperatures today and during those ice ages is only about 5 degrees Celsius (9 degrees Fahrenheit), and these swings happen slowly, over hundreds of thousands of years.
Now, with concentrations of greenhouse gases rising, Earth's remaining ice sheets (such as Greenland and Antarctica) are starting to melt too. The extra water could potentially raise sea levels significantly.
As the mercury rises, the climate can change in unexpected ways. In addition to sea levels rising, weather can become more extreme. This means more intense major storms, more rain followed by longer and drier droughts (a challenge for growing crops), changes in the ranges in which plants and animals can live, and loss of water supplies that have historically come from glaciers.
Scientists are already seeing some of these changes occurring more quickly than they had expected. According to the Intergovernmental Panel on Climate Change, eleven of the twelve hottest years since thermometer readings became available occurred between 1995 and 2006.