ROCKY REX'S SCIENCE BITES

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 Organisatio...

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 the cause of 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...

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 he  Gulf Stream  transports vast amounts of heat north, from the equator to the pole, passing off the East Coast of the U.S. and into the North Atlantic. The  Northern Hemisphere winter of 2014-15  was the warmest on record globally, according to the National Oceanic and Atmospheric Administration.  But one area of the  North Atlantic   was the coldest on record... shown in blue on this map. This cold pool may be  an indicator of a dramatic slowdown in the  Gulf Stream. A slowdown like this in the current has not happened for a very long time, perhaps as long as 1,000 years.  It is possibly related to the melting of the  Greenland  ice sheet.  The  freshwater  from the ice sheet  is  lighter  than heavier, salty water that usually occupies that area.  It tends to sit on top of the water,  interfering with the sinking of dense, cold and salt-rich water. The Gulf Stream transpo...

The December 2015 globally-averaged temperature across land and ocean surfaces was 13.31 °C,   according to the US  National Oceanic and Atmospheric Administration. That is 1.11°C above the 20 th  century December average of 12.2°C. December also marks the eighth consecutive month (since April 2015) with a global monthly temperature breaking the record for its respective month. This information for December 2015 adds to the results for previous months of the year to show that 2015 was  Earth’s warmest year since records began in 1880.

The year  2015  ranks as Earth’s warmest year since records began in 1880. This is reported by scientists from NASA and the National Oceanic and Atmospheric Administration.   The average surface temperature has risen about 1.0 degree Celsius since the late-19th century. Globally-averaged temperatures in 2015 beat the previous record set in 2014 by 0.13 degrees Celsius .  NASA analysis estimates 2015 was the warmest year with 94% certainty. Most of the warming occurred in the past 35 years, with 15 of the 16 warmest years on record occurring since 2001. 2015 was the first time the global average temperature was 1 degree Celsius or more above the 1880-1899 average. Global annual average temperature relative to 1961-1990 based on the three major global temperature datasets (HadCrut4, NASA GisTEMP and NOAA).  Red bars indicate an El Niño year, blue is La Niña and grey is neutral .  Source: World Meteorological Oroganisation...

Coal, oil and natural gas are  fossil fuels . When they are burned, they  change the Earth's atmosphere. How is that possible?       C oal  is a good example. Coal was formed  hundreds of millions of years ago . Geologists say that a three-metre (10-foot) coal seam took between  12,000 and 60,000 years  to form . Ancient trees and other plants lived, died and were fossilised. All those plants took  carbon dioxide  out of the atmosphere.  Some larger coal seams are, for example, 10 metres thick. They took around  40,000 years to form,  but have been mined and burned in a little over  100 years. The fastest rise of CO 2  in the air seen in   the ice core record (800,000 years)  is  20 ppm in 1000 years. The CO 2  level in the atmosphere is now rising at around  20 ppm per decade . The  carbon  joins up with  oxygen  when it burns. Eac...

Carbon sinks  are natural systems that suck up and store  carbon dioxide  from the atmosphere. The main natural carbon sinks are  plants, the ocean and  soil.   Plants  grab carbon dioxide from the atmosphere to use in  photosynthesis ; some of this carbon is transferred to soil as plants die and decompose.  The  oceans  are a major carbon storage system for carbon dioxide.  Marine life also takes up the gas for photosynthesis, while some carbon dioxide simply dissolves in the seawater. 35 billion tonnes  of CO2 are produced each year by human activities. Currently, natural processes are absorbing about half of that. The figure of 33.4 billion metric tonnes of carbon dioxide is for 2010.   The remaining carbon dioxide is building up in the atmosphere.  

Healthy  coral  can be very colourful. Some coral reefs have started to look rather different. This is called ' coral bleaching '. To understand this, we need to start by looking at corals. Corals are animals that make a framework around them  that looks like rock. Coral animals ( polyps ) have tiny  plants -  algae  - living in their tissues. The algae provide food to the corals, which they produce by  photosynthesis . Reef-building corals only live in a limited temperature range. Like porridge, they should be 'not too hot and not too cold'. Coral reefs  are concentrated in a band around the equator, between 30 ° N and 30 ° S latitude. Algae in corals need light Corals grow in warm, clear, shallow waters that receive plenty of light. Most corals grow in the warmest water they can stand (about 85° F or 29° C).  This means that slight increases in ocean temperature can harm corals. High sea temperature is the main reas...