ROCKY REX'S SCIENCE BITES

Earth's polar regions are warming faster than the rest of the planet. One reason is that energy is carried to the poles by large weather systems. The  Arctic   includes an  ocean covered by sea ice . Arctic sea ice  melts in Summer and then refreezes in Winter. The area of Arctic sea ice is largest in March each year, and at its lowest each September. It is reducing over time - the graph comes from the US  National Snow and Ice Data Center. Research suggests   the remarkable decline of   Arctic sea ice over  the last century is far beyond anything seen for a long time.   The  Antarctic  is a  continent covered by ice , unlike the ocean in the Arctic. The sea ice surrounding Antarctica melts almost to the coast each summer. Ice shelves  around Antarctica are also affected by global warming. For a useful comparison of Antarctic and Arctic sea ice follow this link…… Arctic ...

There were some very unusual weather events in 2010, which may be a warning of future effects of climate change. Each time there are  extreme weather events , people debate "Is there a link to climate change?" It might be hard to prove in many cases. Some recent events, however, are extraordinary. The phrase  'weather on steroids'  has been used to describe these events. In 2010,  China  and  Brazil  had serious droughts, and in the first part of the year the Northern Hemisphere warmed fast, melting the winter snow cover very quickly. The picture shows the dried-up  River Negro  in Brazil, with a bridge in the distance.   But the biggest events were  the  heatwave in Russia  and the  flooding in Pakistan . In  Pakistan ,  Government officials said that from  July 28 to Aug. 3, parts of Khyber Pakhtunkhwa province recorded almost  12 feet (3.6 metres) of rainfall  in one week .  ...

Around 34 million years ago, at the  Eocene-Oligocene Transition  (EOT), the Earth was undergoing a period of global cooling.  Antarctica  changed from a green forested continent to the land of ice we know today.  The cooling was partly caused by  declining atmospheric carbon dioxide  levels, but it also coincides with changes in the geography of the Southern Ocean. Around 55 million years ago, CO2 levels had risen during the  Paleocene-Eocene Thermal Maximum   (PETM). Weathering of the newly-building  Himalayas  caused CO2 levels to begin to fall. CO2 in rain makes a weak acid, which causes chemical weathering (especially of carbonate rocks like limestone, but of other rocks as well). Rivers carry the carbon compounds down to the oceans, where various processes (such as the formation of calcareous shells by organisms) eventually deposit the material on the ocean floor. This is the long, slow, part of the  c...

Animals  are reacting to climate change very quickly. Some move to higher places,  others move north or south. Dragonflies  love warmer temperatures. UK dragonflies have mainly stayed in the south of the country, until recently. Ruddy Darter ( Sympetrum sanguineum ) Since 1980, 34 out of the 37 British species of dragonfly have expanded their range northwards by an average of 74km. That is over 2km per year..... nearly 6 metres per day. For example, the  ruddy darter  ( Sympetrum sanguineum ) and the  hairy dragonfly , ( Brachytron pratense ), have moved into north-west England.  This is evidence that the UK’s climate is growing warmer. "So much has happened to  dragonflies  in Britain since the 1990s that there is a most compelling case for the Government to adopt them as indicators of climate change", said  Steve Brooks . He is a London Natural History Museum research entomologist, with a special interest in the ...

As global warming continues, heat goes into  all parts of the Earth's systems. The Earth is gaining more heat than it loses, and most of that heat is going into the oceans. More heat is going into the upper parts of  the oceans. The water in the oceans is expanding, which is one reason sea level is rising. The deepest oceans are still cold. Some of the heat is involved in melting ice, including Arctic sea ice. The recent reduction in Arctic sea ice is very dramatic. The  ice sheets of Greenland and Antarctica  are also melting.

The climate has changed before. When people say "It's changed before without people, so people can't be involved this time" ....think of  forest fires . Fires happened throughout time, does that mean people can't start fires? Ice ages, warm times ... the geological record in the rocks shows many events. Even so,  the current changes are very unusual . Note that in the "Years before present" scale, zero = 1950 AD Graph based on a  paper  published in 2013 The recent rise in temperature is very fast. What other kinds of changes are happening? Geologists   have compared the past with the present. This report - Climate Change Evidence: The Geological Society of London explains what they have discovered. This is based on part of that report: "Before the current warming trend began, temperatures were declining. This cooling took Earth’s climate into the ‘Little Ice Age’ (1450 – 1850).  Calculations indic...

The invention of the name " Greenland"  may mark the start of the advertising industry. The  Saga of the Greenlanders  tells how  Erik the Red , the Icelandic Viking who wanted to get people to join his planned settlement, called it Greenland because a pleasant name would attract more settlers: He called the land which he had found Greenland, because, quoth he, "people will be attracted thither, if the land has a good name."  The  ice sheet  on Greenland covers most of this huge island. Greenland is losing ice, and the mass of ice lost is measured by satellites called GRACE. A survey of Greenland's glaciers  has shown they are speeding up. The speed has increased by about 30% in 10 years. A paper published in June 2019  predicts that  Greenland will very likely become ice free within a millennium without substantial reductions in greenhouse gas emissions. A new NASA project called  Oceans Melting Greenland (OMG)  ...

Five major  mass extinction  events are recorded in the rock record of the last 600 million years. The biggest extinction was at the end of the  Permian , around 252 million years ago. It is called the  End-Permian mass extinction. Only about 8% of species survived to live on in the Triassic Period. Field photograph of the Permian-Triassic boundary (PTB) section at Xiakou, Hubei Province,  South China. The event played out over 60,000 years. Acidification of the oceans  lasted for about 10,000 years. Two separate pulses of CO2 into the atmosphere - a "one-two punch" - may have been involved in the die-off, according to  new research. CO2 was released by massive volcanism from the  Siberian Traps , now represented as a large region of volcanic rock.  Researchers have found fly ash, one of the products of coal combustion, in rocks laid down just before this extinction event. A large amount of coal ha...

El Niño  is an  oscillation of the ocean-atmosphere system in the tropical Pacific , and has important consequences for weather around the world. El Niño  happens every three to seven years. “El Niño” is Spanish for “The Little Boy”. Peruvian fishermen named the event many years ago. They noticed that every few years around Christmas, virtually no fish could be found in the unusually warm waters.  El Niño is marked by  unusually warm ocean temperatures  in the Equatorial Pacific. The opposite conditions are called  La Nina  (The Little Girl), characterized by  unusually cold ocean temperatures  in the Equatorial Pacific.  El Nino clearly affects global temperatures. One piece of evidence that world temperatures are rising is that every  La Nina  ‘year’ since 1998 was warmer than every  El Nino  ‘year’ before 1995:   As the Earth warms, each El Nino 'rides' on a higher base-line global tem...

For many years, fishermen in the  North Sea , between Britain and Denmark, have found  fossil bones  in their nets. This fossil catch has yielded over 200 tons of fossil bones, and over 15,000 mammoth teeth.    The bones include remains of  mammoths , three different species of  woolly rhinos ,  hippos ,  lions ,  bears ,  wild horses ,  bison ,  elk ,  reindeer ,  hyenas ,  wolves ,   and  Sabre tooth  cats of at least two species.    They tell us about a whole community of animals. Beneath the North Sea lies a lost landscape. This land was as big as modern Britain - hills and valleys, rivers and forests, marsh and moor.  Sometimes warm and marshy, and at other times a frozen tundra. This has been named  "Doggerland". "Doggerland"  is a name given to  a vast lowland plain, with the northern coastline stretching from Shetland to Jutland. ...

What do scientists who research climate change say? Professor Tim Palmer FRS, Royal Society Research Professor in Climate Physics, University of Oxford: “T he threat of dangerous man-made changes to global climate is quite unequivocal.  It follows that if we want to reduce this threat, we must cut our emissions of greenhouse gases." Professor John Shepherd FRS, Ocean & Earth Science, University of Southampton: “The evidence is very clear that the world is warming, and that human activities are the main cause.  Natural changes and fluctuations do occur but they are relatively small." Professor Joanna Haigh CBE FRS, Professor of Atmospheric Physics, Imperial College London: “ The concentration of carbon dioxide in the Earth’s atmosphere now exceeds anything it has experienced in the past 3 million years and its continuing upward trend is almost certain to result in further global warming." Professor Sir Brian Hoskins FRS, Director of the Grantham...

The climate can react to sudden shocks. The weather in  1816  was very strange.  Spring arrived, but then everything seemed to turn backward, as cold temperatures returned.  The sky seemed permanently overcast.  T he lack of sunlight became so  severe that farmers lost their crops. Food shortages were reported in Ireland, France, England, and the United States. 1816 became known as  "The Year without a Summer"  or "18-hundred-and-frozen-to-death". It was over 100 years before anyone understood the reason for this weather disaster. The eruption of an enormous volcano on a remote island in the Indian Ocean a year earlier had  thrown enormous amounts of volcanic ash  into the upper atmosphere. The dust from  Mount Tambora , which had erupted in early April 1815, had shrouded the globe.  With sunlight blocked, 1816 did not have a normal summer. In Switzer...