What are the main indicators of Climate Change?

What is the Greenhouse Effect?

The term greenhouse is used in conjunction with the phenomenon known as the greenhouse effect.

• Energy from the sun drives the earth’s weather and climate, and heats the earth’s surface;
• In turn, the earth radiates energy back into space;
• Some atmospheric gases (water vapor, carbon dioxide, and other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse;
• These gases are therefore known as greenhouse gases;
• The greenhouse effect is the rise in temperature on Earth as certain gases in the atmosphere trap energy.

Six main greenhouse gases are carbon dioxide (CO₂), methane (CH₄) (which is 20 times as potent a greenhouse gas as carbon dioxide) and nitrous oxide (N₂O), plus three fluorinated industrial gases: hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF₆). Water vapor is also considered a greenhouse gas.

The Greenhouse effect is natural. What do we have to do with it?

Many of these greenhouse gases are actually life-enabling, for without them, heat would escape back into space and the Earth’s average temperature would be a lot colder.

However, if the greenhouse effect becomes stronger, then more heat gets trapped than needed, and the Earth might become less habitable for humans, plants and animals.

Carbon dioxide, though not the most potent of greenhouse gases, is the most significant one. Human activity has caused an imbalance in the natural cycle of the greenhouse effect and related processes. NASA’s Earth Observatory is worth quoting the effect human activity is having on the natural carbon cycle, for example:

Another way of looking at this is with a simple analogy: consider salt and human health:

• A small amount of salt is essential for human life;
• Slightly more salt in our diet often makes food tastier;
• Too much salt can be harmful to our health.

In a similar way, greenhouse gases are essential for our planet; the planet may be able to deal with slightly increased levels of such gases, but too much will affect the health of the whole planet.

The other difference between the natural carbon cycle and human-induced climate change is that the latter is rapid. This means that ecosystems have less chance of adapting to the changes that will result and so the effects felt will be worse and more dramatic it things continue along the current trajectory.

The climate has always varied in the past. How is this any different?

Doesn’t recent record cold weather disprove Global Warming?

Has global warming paused due to recent surface temperature drops?

Most global warming is going into the oceans

Rapid changes in global temperature

Increased greenhouse gases and the greenhouse effect has contributed to an overall warming of the Earth’s climate, leading to a global warming (even though some regions may experience cooling, or wetter weather, while the temperature of the planet on average would rise).

Consider also the following:

At the end of the 1990s, the World Meteorological Organization (WMO) had noted that not only was the 1990s the warmest decade but at the time, the 1900s was the warmest century during the last 1,000 years.

It is the rapid pace at which the temperature will rise that will result in many negative impacts to humans and the environment and this why there is such a world-wide concern.

Extreme Weather Patterns

Most scientists believe that the warming of the climate will lead to more extreme weather patterns such as:

• More hurricanes and drought;
• Longer spells of dry heat or intense rain (depending on where you are in the world);
• Scientists have pointed out that Northern Europe could be severely affected with colder weather if climate change continues, as the arctic begins to melt and send fresher waters further south. It would effectively cut off the Gulf Stream that brings warmth from the Gulf of Mexico, keeping countries such as Britain warmer than expected;
• In South Asia, the Himalayan glaciers could retreat causing water scarcity in the long run.

While many environmental groups have been warning about extreme weather conditions for a few years, the World Meteorological Organization announced in July 2003 that Recent scientific assessments indicate that, as the global temperatures continue to warm due to climate change, the number and intensity of extreme events might increase.

The WMO also notes that New record extreme events occur every year somewhere in the globe, but in recent years the number of such extremes have been increasing. (The WMO limits the definition of extreme events to high temperatures, low temperatures and high rainfall amounts and droughts.) The U.K’s Independent newspaper described the WMO’s announcement as unprecedented and astonishing because it came from a respected United Nations organization not an environmental group!

Ecosystem Impacts

With global warming on the increase and species’ habitats on the decrease, the chances for various ecosystems to adapt naturally are diminishing.

Many studies have pointed out that the rates of extinction of animal and plant species, and the temperature changes around the world since the industrial revolution, have been significantly different to normal expectations.

An analysis of population trends, climate change, increasing pollution and emerging diseases found that 40 percent of deaths in the world could be attributed to environmental factors.

Rising Sea Levels

Water expands when heated, and sea levels are expected to rise due to climate change. Rising sea levels will also result as the polar caps begin to melt.

Rising sea levels is already affecting many small islands.

The WorldWatch Institute reports that [t]he Earth’s ice cover is melting in more places and at higher rates than at any time since record keeping began. (March 6, 2000).

Rising sea levels will impact many coastlines, and a large mass of humanity lives near the coasts or by major rivers.

Differences in Greenhouse Gas Emission Around the World

As the World Resources Institute highlights there is a huge contrast between developed/industrialized nations and poorer developing countries in greenhouse emissions, as well as the reasons for those emissions. For example:

• In terms of historical emissions, industrialized countries account for roughly 80% of the carbon dioxide buildup in the atmosphere to date. Since 1950, the U.S. has emitted a cumulative total of roughly 50.7 billion tons of carbon, while China (4.6 times more populous) and India (3.5 times more populous) have emitted only 15.7 and 4.2 billion tons respectively (although their numbers will rise).
• Annually, more than 60 percent of global industrial carbon dioxide emissions originate in industrialized countries, where only about 20 percent of the world’s population resides.
• Much of the growth in emissions in developing countries results from the provision of basic human needs for growing populations, while emissions in industrialized countries contribute to growth in a standard of living that is already far above that of the average person worldwide. This is exemplified by the large contrasts in per capita carbons emissions between industrialized and developing countries. Per capita emissions of carbon in the U.S. are over 20 times higher than India, 12 times higher than Brazil and seven times higher than China.

At the 1997 Kyoto Conference, industrialized countries were committed to an overall reduction of emissions of greenhouse gases to 5.2% below 1990 levels for the period 2008—2012. (The Intergovernmental Panel on Climate Change (IPCC) said in its 1990 report that a 60% reduction in emissions was needed…)

The United States is the World’s Largest Emitter of Greenhouse Gases Per Capita

Around 2007, China surpassed the US as the world’s largest emitter of greenhouse gases in terms of total output. Per person (per capita), however, China’s emissions are much smaller.

Until recently, the United States was the world’s largest emitter of greenhouse gases. However, it remains the largest emitter when measured in terms of emissions per person.

Due to its much longer period of industrialization, the US has emitted far more into the atmosphere than China (greenhouse gases such as CO₂ linger on in the atmosphere for decades).

In addition, the US:

• Accounts for roughly four percent of the world’s population;
• Accounts for approximately 20% of global emissions and some 40% of industrialized country emissions;

The previously 15-member European Union is also large Emitter

The previously 15 member-nations European Union (E.U.), if considered as a whole (for it is more comparable to the U.S.):

• Accounts for roughly 3 percent of the world’s population;
• Accounts for around 10% of global emissions and 24% of industrialized countries’ man-made emissions of the six main gases;
• Recent years have seen a reduction in emissions from those initial 15-member states. However,

Rich Nations Have Outsourced Their Carbon Emissions

Developing Countries Affected Most

Bush Administration Accused of Silencing its own Climate Scientists