ROCKY REX'S SCIENCE BITES

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 energy that affects the climate on the Earth originates from the Sun. The energy emitted by the Sun passes through space, until it hits the Earth’s atmosphere. Only about 40% of the solar energy hitting the top of the atmosphere passes through to the Earth’s surface. The rest is reflected, or absorbed by the atmosphere.  Here are some of the many factors that can cause the Earth's climate to get hotter or colder.   These factors are sometimes referred to as 'forcings'. Strength of the sun The energy output of the sun is not constant, it varies over time. Recently it has been reducing slightly. The next two factors are astronomical cycles. Changes in the Earth’s orbit The Earth’s orbit around the Sun is an ellipse, not a circle, but the ellipse changes shape. Sometimes it is almost circular - and the Earth stays approximately the same distance from the Sun as it orbits. At other times the ellipse is more stretched, so that the Earth move...

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 in...

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 new NASA project called  Oceans Melting Greenland (OMG)   will observe changing water temperatures on the continental shelf surrounding Greenland, and how marine glaciers react to the presence of warm, salty Atlantic water. Updates a...

This graph shows how temperatures have changed over the last 11,000 years, since the end of the last  glacial stage . The graph uses data from  modern temperature records , plus information about the past from  a research paper  that combined data from over 70 different scientific studies. The next graph adds data from even further back in time: The  green part  covers the time as  the last  glacial stage  was coming to an end, and the great ice sheets were melting. The last glacial stage ended about 10,000 years ago.  Then, for nearly 5,000 years, global temperature was  surprisingly stable .  In the next 5,000 years, up to about 1800, global temperature  declined  by about 0.7 deg.C. There were  some variations  in that slow decline: From 1800 until 2000, temperature  rose by about 0.8 deg.C,  according to the   World Meteorological Organisation...

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 t...

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 of 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.  The...

In the latest survey by Dr James Powell, 69,402 out of 69,406 climate change researchers accept human activity is causing global warming. 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 cont...

Climate reacts to sudden shocks. The weather in  1816  was unprecedented.  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. 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 Switzerland, the dismal summer of 1816 led to the writing of a famous story.  A group of writers, including...

Norway  is dotted with small glaciers, and 'permanent' snow patches . Around 7,000 years ago (5000 BC) the Earth was enjoying a warm climate: Then it cooled, allowing those icy areas to form. Now those glaciers and patches of perennial ice in the high mountains of Southern Norway have started to melt again, as the Earth is warming.  They contain all sorts of archaeological treasures. Anything from ancient shoes to 5000-year-old arrowheads.  As a result a new kind of archaeology has begun -  Glacial archaeology . In 2006,  an amateur archaeologist came across an amazingly well-preserved  ancient leather shoe  in   the Lendbreen ice patch in Norway.  When the shoe was examined and tested, archaeologists discovered the shoe was over 3,000 years old, and dated from the  Bronze Age . "Actually we should be slowly approaching a new ice age.  But in the past 20 years we have witnessed artefacts turning up in summer from i...

The phrase ' ocean acidification ' means that the  pH of seawater  is falling. The  pH scale  is used by scientists to describe  strength  of acids and alkalis.  Sea water  normally had a pH around 8.2  It has now reduced to 8.1, and will continue to reduce, as more CO 2  is added to the air by human activities. Some of the extra CO 2  in the air  dissolves  in the sea, and this affects sealife. Here is what one expert scientist has said about this - "A drop of 0.1-unit pH is equivalent to about a 26% increase in the ocean hydrogen ion concentration. "pH is likely to drop by 0.3-0.4 units by the end of the 21st century.   "This will increase ocean hydrogen ion concentration (or acidity) by 100-150% above what it was in pre-industrial times." Scott Doney, Senior Scientist, Woods Hole Oceanographic Institution, USA       Humanity's greenhouse gas emissions may be acidifying t...

Every place on earth experiences  12 hours of daylight  twice a year, on the Spring and Autumn Equinox. The Sun is at its lowest path in the sky on the  Winter Solstice .  After that day, the Sun follows a higher and higher path through the sky each day, until it is in the sky for exactly 12 hours.  On the  Spring Equinox , the Sun rises almost exactly in the east, travels through the sky for 12 hours, and sets almost exactly in the west.  The March equinox   marks the moment the Sun appears to cross the  celestial equator  – the imaginary line in the sky above the Earth’s equator – from south to north.  After the  March equinox, northern days continue to lengthen until the June solstice.