What is global warming?

What is causing global warming?

Is global warming really happening?

What are the effects of global warming?

A few degrees warmer doesn't sound that bad, what's the big deal?

How much warmer is the Earth likely to become?

Scientists say some warming will happen no matter what we do, why act now?

ANSWERS

What is global warming?

Global warming is an increase in Earth's average surface temperature. 11 of the last 12 years (1995-2006) have been the warmest years on record, and these are part of a trend that goes back to the start of the industrial revolution. The most likely cause of the current warming is a dramatic increase of greenhouse gases caused by human activity, although other factors may also play a role.

Why is global warming important to moms?

Global warming is likely to have an impact on our children’s future.  The Earth has experienced major changes in the past century due to human activity. Warming in the next century is likely to be much greater unless we act now to leave our children a healthy planet. 

What are Greenhouse Gases?

Greenhouse gases warm the earth's surface by trapping heat within the atmosphere.

Carbon dioxide and other greenhouse gases warm the surface of the planet by trapping heat in the atmosphere.  Some greenhouse gases occur naturally in the atmosphere, while others result from human activities.  Naturally occurring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone.  They help keep our planet livable.  The overabundance of greenhouse gases is causing the earth to heat up.

There are many ways that humans impact the levels of naturally occurring greenhouse gases. Most important, carbon dioxide is released to the atmosphere when fossil fuels (oil, natural gas, and coal), wood, solid waste, and agricultural products are burned. Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from the decomposition of organic wastes in municipal solid waste landfills, and the raising of livestock. Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of solid waste and fossil fuels. Scientists are able to distinguish between the gases caused by human activities and the gases that are naturally occurring by examining their chemical properties.  In addition, humans create greenhouse gases that don't naturally occur at all. These include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6), which are generated in a variety of industrial processes.

WHAT IS CAUSING GLOBAL WARMING?

What is causing global warming?

We are! While there are natural fluctuations in global temperature, the rate and magnitude of recent warming indicate a human cause.  We are doing this primarily by adding large amounts of heat-trapping gases to the atmosphere. Fossil fuel use is the main culprit. Every time we drive a car, use electricity from coal-fired power plants, or heat our homes with oil or natural gas, we release carbon dioxide and other heat-trapping gases into the air. The second most important human source of greenhouse gases is deforestation, mainly in the tropics, and other land-use changes.  Carbon dioxide levels have increased  by 40% since pre-industrial times.

Which country's emissions are the highest?

The United States. Americans comprise just 4 percent of the world's population but produce the lion’s share of carbon dioxide pollution from fossil-fuel burning: 25 percent. In fact, the United States emits more carbon dioxide than China, India and Japan, combined. China is not far behind. The International Energy Agency has concluded that China, with 4 times the US population, will surpass US emissions in 2009.

IS GLOBAL WARMING REALLY HAPPENING? HOW DO WE KNOW?

Is global warming really happening?

Yes – the facts of warming are not in dispute.  There are many ways to measure the progress of warming, and they all agree the earth is heating up.  We see the effects in rising surface air temperatures, rising ocean temperatures, melting of glaciers and snowfields, and rising sea level.

What is the most reliable source of scientific information on global warming?

We recommend the reports from the Intergovernmental Panel on Climate Change (IPCC). The IPCC was established in 1988 to examine the most current scientific information on global warming and climate change. The IPCC does not carry out research. Rather, the IPCC reviews all of the published and peer-reviewed scientific information produced in recent years to assess what we know about the global climate, why and how it is changing, what it means for people and the environment, and what can be done about it.  Over 1,250 authors and 2,500 scientific expert reviewers from more than 130 countries contributed to the IPCC's most recent report, Climate Change 2007: The Fourth Assessment Report.

Because the IPCC strives to achieve consensus among a very large group of authors, it tends to be conservative in its conclusions. Nonetheless, it serves a critical role as a consolidator of information from the whole spectrum of climate change science. You can learn more about the IPCC at www.ipcc.ch and www.ucsusa.org/global_warming/science/the-ipcc.html

For a good kid-friendly resource, we recommend the EPA’s website:  http://www.epa.gov/climatechange/kids/

WHAT ARE THE EFFECTS OF GLOBAL WARMING?

What are the effects of global warming?

Global warming is hurting many species, coastal areas and people.  Future warming will only make matters worse. Just how much worse depends on us and how quickly we take action to stop global warming. Effects of global warming include heat waves, decreased snow packs, disrupted water supplies, melting glaciers, sea ice and polar ice caps, rise in sea level, instability in permafrost regions, more extreme rainfall events, floods and droughts, more wildfires, more intense hurricanes and stronger storm surges in coastal areas, poleward migration in infectious diseases (such as malaria), increases in allergenic pollens, species extinction, and poleward and upward (elevation) shifts in ranges of natural and cultivated plant and animal species.  For more information, see www.nctimes.com/articles/2007/04/05/science/17_41_173_31_07.txt

Is global warming causing more intense hurricanes?  Is hurricane damage increasing?

Possibly.  Warmer ocean temperatures can strengthen the hurricane’s intensity. Recent scientific evidence suggests a link between the destructive power of hurricanes and higher ocean temperatures, driven in large part by global warming. In addition, even the gradual sea-level rise accompanying global warming increases the storm surge.  With rapid population growth in coastal regions placing many more people and structures in the path of these storms, there is a much greater risk of casualties, property damage, and financial hardship when these storms make landfall.

This winter was really cold where I live. Has global warming stopped?

No – one odd season does not break a trend. Even with global warming, we will still have some years that will be warmer or colder than average in any location. When some places are warmer, others tend to be colder, so much of this variation averages out when we look at the temperatures averaged around the entire world, but even then there are small year-to-year fluctuations.  Natural events such as large volcanic eruptions can noticeably affect temperatures around the world for a couple of years.  For these reasons, we have to look at many years of temperature records to be sure that global warming is real.  The occurrence of one strangely warm/cold/snowy/dry season does not mean the long-term trend is changing.

Why is it warming faster in the Arctic?

Because water is darker than snow. It appears the Arctic regions are warming faster than elsewhere due to the 'ice albedo feedback'.  Snow looks white because it reflects back most of the sunlight that hits it, which means that parts of the ocean covered in sea ice and snow don't absorb much sunlight even in the summer.  Once the sea ice starts to melt, though, the white snow is replaced with dark water, which is highly absorbing.  This is called a 'positive feedback', where once the warming gets started it tends to accelerate on its own. You can find more information about global warming and the Arctic at www.pewclimate.org/arctic_qa.cfm.

WHAT'S THE BIG DEAL? (WHY SHOULD I CARE?)

A few degrees warmer doesn't sound that bad, what's the big deal?

It depends where you live. There are two parts to this issue: First, the temperature increases from global warming will not be evenly distributed – some areas will only get slightly warmer, while others will see large changes.  Secondly, there are parts of the world where a small temperature rise can make a really big difference. For instance, big portions of the world's population (like the western USA or northern India) rely on winter snowfall to provide summer water supplies. A small difference in temperature can mean a big difference in how much snow collects during the winter. This can lead to wintertime floods and summertime droughts.  What has happened already is serious and it will probably pale in comparison to future changes. The actions we take today will determine what sort of world our children will inherit. 

I don't live near Antarctica, so why should I worry about melting ice sheets?

Antarctica is a climate giant. Antarctica holds the majority of all of the earth's fresh water trapped in its enormous ice sheets. Warming can destabilize ice flow, and if the more vulnerable West Antarctic ice sheet collapsed, it would raise the sea level around the whole globe by over 15 feet.  Most experts think Antarctic ice sheet collapse is unlikely to happen soon.  Antarctica is experiencing more snowfall and virtually none of it melts, but its ice flow to the sea is also increasing, so it is uncertain whether Antarctica’s ice sheets are growing or shrinking.  Greenland could experience a similar fate, however.  Greenland is melting near the edges, so it is more worrisome.  The thermal expansion of sea water and the runoff from glaciers is the greatest current source of sea level rise (about 1 inch per decade).  This doesn’t sound like much but rising sea level in our lifetimes will have a big impact on coastal communities. (See http://pubs.usgs.gov/fs/fs2-00 for more information.) Even if you don't live near the ocean, you still might care about the ice sheets: one theory for the onset of ice ages is that the deep ocean circulations that move heat from the equator to the poles can be shut down by a rapid melting of ice.

What are the implications of global warming on human health?

As global warming changes our climate and environment, it will also affect our health. More people will suffer from disease and injury due to heat waves, floods, storms, fires and droughts.  Climate scientists expect that most dry areas (such as Mexico and the Southwestern US) will get drier, stressing large populations of subsistence farmers in these regions.  Malnutrition and consequent disorders will rise, with negative impacts on child development. Mosquito-born diseases, such as malaria, have migrated to new regions and higher elevations. Cardio-respiratory diseases will increase, due to higher concentrations of ground level ozone. As carbon dioxide levels boost the production of plants like ragweed, allergies and hay fever will also increase. We will see more heat-related deaths, especially in vulnerable portions of the population, such as the elderly, very young, chronically sick and socially isolated, that cannot adapt as easily to extreme heat. Diarrheal disease will increase.

An article from LiveScience (www.livescience.com/environment/070222_climate_fever.html) suggests one way that warmer temperatures could affect children's health.  An Australian researcher compared emergency room visits for children under age six to climate data, and found that higher outside temperatures were related to more visits by children with fevers and gastroenteritis.

I don't live near the coast, so why should I worry about hurricanes?

The economic and human impact of hurricanes affects us all.  The sea level has already begun to rise and will continue to rise as oceans warm and glaciers melt. Rising sea level means higher storm surges, even from relatively minor storms, which increases coastal flooding and subsequent storm damage and loss of life along coasts. In addition, the associated heavy rains can extend hundreds of miles inland, further increasing the risk of inland flooding.

WHAT WILL HAPPEN IN THE FUTURE?

How much warmer is the Earth likely to become?

Several more degrees. The latest IPCC report estimates that if we fail to take action, the "business-as-usual" scenario, the Earth's average surface temperature is projected to increase between 2.5° and 10.4°F (1.4°-5.8°C) between 1990 and 2100, with most projections around 4-8°F. Warming will be larger over land and two to three times as large in the polar regions.

Will responding to global warming hurt the economy?

Not as much as not responding. The Stern Review, an assessment on the impacts of climate change and the economic cost, concludes the “benefits of strong and early action far outweigh the negative costs of not acting.” See http://www.hm-treasury.gov.uk/sternreview_index.htm for the full report.  We already have many energy technologies that can wean us from fossil fuels, some of which (such as wind power, capturing the carbon dioxide from coal-burning power plants, and energy efficiency improvements) would cost us little more than ‘business as usual’.  With further research investment, solar power may become a cheap long-term solution to the world’s energy needs and other renewable technologies such as biofuels may also play important roles.  ‘Decarbonizing’ our energy over the next few decades is estimated to cost the US less than fighting the Iraq war.

What might the future look like for my children?

Climate change will affect the basic elements of life for people around the world. Access to water, food production, health, and the environment will be impacted. Hundreds of millions of people could suffer hunger, water shortages, extreme weather events, heat waves, wildfires, and coastal flooding as the world warms. One third of the world’s population currently lives in a coastal area. As mothers, it is our duty to take immediate action to stop global warming and to safeguard our children's future.

WHAT CAN I DO?

Scientists say some warming will happen no matter what we do, why act now?

We can change the outcome if we act decisively and soon.  Although increased levels of carbon dioxide in the atmosphere will last for decades or centuries, the energy choices we make today can still greatly influence the climate our children and grandchildren inherit. We have the technology to increase energy efficiency, significantly reduce these emissions from our energy and land use, and secure a high quality of life for future generations. We have a small window of time and we must act now to avoid dangerous consequences.

What can I do to stop global warming?

A lot!  We are optimistic that the most drastic scenarios won't happen because people will take immediate action to stop the increase in emissions causing global warming. We must act now in order to secure our children’s future. 

Take Action Today!