Topical Science March 2017

M A R C H

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TOPICAL SCIENCE Author: Margaret Franklin

Climate & Weather

Our Changing Weather Weather is always a talking point in Ireland. It varies from day to day and sometimes we seem to have four seasons in one day! As we live on a small island on the western shore of the Atlantic Ocean and the prevailing winds come from the south-west, we get a lot of rain. This is not always welcome, but it keeps our grass green and ensures we do not suffer from drought. We are lucky to lie in the path of the Gulf Stream, a warm current coming from the Gulf of Mexico. This causes our climate to be warmer than might be expected for our Latitude in the mid 50s.

In this issue Weather We are familiar with weather forecasts on radio and TV. They predict rainfall, sunshine, wind speeds, temperature and atmospheric pressure over short periods of a few days.

Climate Met Eireann has published Long Term Climate Averages for the 30 years from 1981 to 2010 in Ireland. It reports that rainfall has increased and that our average temperature has increased slightly, during this period, compared to the previous 30-year period.

While our weather may vary from day to day and from season to season, the longterm averages of weather conditions, such as rainfall and temperature, remain relatively constant. This long-term view of our weather is what we call climate.

Meteorologists regard 30 years as a sufficiently long period for this purpose and the Meteorological services in many countries now publish 30 year reports. This allows us to monitor climate change.

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Climate Change Europe enjoyed warm weather from the year 900 to 1300, in what became known as ‘The Medieval Warm Period’. This was long before the industrial revolution and is unlikely to have been caused by human activities. Between 1350 and 1850, there was a ‘Little Ice Age’ with very cold winters in parts of the northern hemisphere.

This was particularly marked in 1709 when the winter was extremely severe.

The 1980s was the hottest decade on record (up to then) and 1987 was the warmest year. American scientists attributed the drought of 1988 to global warming. The United Nations set up the IPCC (Intergovernmental Panel on Climate Change) which published its first report in 1990. It announced that the planet had warmed by 0.5°C in the past century.

The volcanic eruption of Mount Pinatubo in the Philippines in 1991 threw debris into the stratosphere that shielded the Earth from solar energy. This caused the average temperature to fall for two years before rising again. This event showed that global temperatures are very sensitive to disruption.

In 1827, the French scientist Jean-Baptiste Fourier proposed the so-called ‘greenhouse model’ to explain global warming. In 1863, the Irish scientist John Tyndall showed how water vapour can behave as a ‘greenhouse gas’. In the 1890s, Swedish scientist Arrhenius predicted that the buildup of CO2 in the atmosphere, due to the burning of fossil fuels, could cause problems. This seemed to be verified, since, from the 1890s to 1940, average surface air temperatures increased by about 0.25 °C. But this trend was reversed to a certain extent during the following 30 years, as a global cooling of 0.2°C occurred between 1940 and 1970.

The Climate Change Convention was signed by 154 nations in Rio in 1992. It aimed to reduce emissions from industrialised countries to 1990 levels by the year 2000.

During the 1970s, studies in the US raised concerns about global warming. A conference on the greenhouse effect was held at Villach, Austria, in 1985. It warned that greenhouse gases could cause an increase in the mean global temperature, resulting in a significant rise in sea level.

The conference also listed gases other than CO2 that contribute to global warming (e.g. methane, ozone, CFCs and N2O).

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In 1994,The Alliance of Small Island States demanded a 20% cut in emissions by the year 2005, to prevent their islands from being inundated by rising sea levels. 1995 became the hottest year on record and the IPCC report predicted that, unless action is taken, global temperatures by the year 2100 would rise by between 1°C & 3.5°C. At the second meeting of the Climate Change Convention in 1996, the US agreed to legally binding emissions targets.

Global CO2 emissions started to increase again, and scientists warned that most industrialised countries would not meet the targets set in Rio in 1992.

The Kyoto Protocol was signed in 1997. Targets were set for industrialised nations, to be met by 2010. But it also allowed countries to meet their targets partly by trading emissions permits or by planting forests to absorb CO2. 1997 was even hotter than 1995 and the 1990s turned out to be the hottest decade of the entire millennium.

Our Climate in The New Millennium. In 2000, as a new millennium began, IPCC scientists warned that the world could warm by 6°C within a century. Major floods around the world seemed to indicate that global warming was causing extreme weather events. But talks held in The Hague in November to finalise Kyoto failed to reach agreement.

Different Consequences of Global Warming.

Higher temperatures cause more water to evaporate from the oceans, with the result that maritime countries like Ireland get more rain.

Floods in Enniscorthy, Co. Wexford, in 2015.

But desert areas get even hotter, leading to drought in parts of Africa and California.

In 2001, the new US president, George W Bush, rejected the Kyoto Protocol, believing it would damage the US economy. In 2002, the European Union, Japan and others ratified Kyoto. But not enough countries signed up to it. In 2003, Europe had the hottest summer for 500 years, with an estimated 30,000 fatalities as a result. Greenhouse gases continued to accumulate at an accelerated rate.

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Final Ratification of the Kyoto Protocol.

In 2004, the Russian parliament agreed to ratify Kyoto and in 2005, the Protocol came into force at last. The US and China agreed to a "non-binding dialogue" on reducing emissions. In 2005, researchers demonstrated links between global warming and the accelerated melting of Arctic sea ice. The increasingly strong US hurricanes were also blamed on global warming.

Scientists in the UK warned that the west Antarctic ice sheet was starting to collapse. Al Gore's climate change film ‘An Inconvenient Truth’ became a box-office hit in 2006. The following year, he and the IPPC were awarded the Nobel Peace Prize.

In spite of all this, carbon dioxide emissions were found to be rising even faster than in the 1990s. The UN climate summit in Bali in 2007 agreed on a successor to the Kyoto protocol.

The United States delegation signed up to it. Barack Obama was elected US President in 2008, promising increases in science funding, especially for climate change and energy technology.

The World Conservation Union found that thousands of species, including polar bears, are at risk from climate change. In 2009 In Antarctica, a thin strip of ice protecting the Wilkins ice sheet from collapse broke apart, while the Arctic continued to warm much faster than expected.

In 2012, a UN Conference on Sustainable Development was held in Rio de Janeiro, 20 years after the 1992 Climate Change Convention. Little progress had been made in the previous 20 years. Three years later, the 2015 UN Climate Change Conference was held in Paris. It is also known as COP 21, as it was the 21st yearly session of the Conference of the Parties (COP) to the 1992 UN Framework Convention on Climate Change. The principal outcome was the Paris Agreement, a global agreement on measures to reduce human influence on climate change.

It is time governments listened to what scientists are saying. Meanwhile, we can all try to reduce our own personal carbon footprint, by not wasting energy! https://www.epa.gov/climate-change-science/causes-climate-change http://www.ucsusa.org/global_warming/science_and_impacts/science/human-contribution-to-gwfaq.html#.WKnZTBz5b1w

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