ROCKY REX'S SCIENCE BITES

In a 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 continuing up...

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...

Norway  is dotted with small glaciers, and 'permanent' snow patches . Around 7,000 years ago (5000 BC) the Earth was experiencing 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 fro...

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...

T he  Gulf Stream  transports vast amounts of heat northwards, 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 tr...

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. Each...

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.

Today is the Autumn Equinox in the Northern Hemisphere, and the Spring Equinox in the Southern Hemisphere.   Every place on earth experiences  12 hours of daylight  twice a year, around the Spring and Autumn Equinox. At the  Equinoxes , the Sun rises almost exactly in the east, travels through the sky for 12 hours, and sets almost exactly in the west. The  September equinox   marks the moment the Sun appears to cross the  celestial equator  – the imaginary line in the sky above the Earth’s equator – from north to south.  After the September  equinox, northern days continue to shorten until the December solstice.

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...

Many people think climate change always happens slowly, but that is not the case......rather than hundreds, or thousands, of years, sometimes it can happen in decades. "Abrupt climate change"  was discovered by accident by Russell Coope (1930-2011), over 50 years ago. More recently he said: "We are  messing with the trigger  that causes climate change....the outcome is likely to be ferocious." In the 1950s, Russell Coope was a young geologist. He was studying layers of sediment formed during the  "Ice Ages" , a time geologists call the  Quaternary . He spotted something unusual in a quarry in the English Midlands.   This is his own description of what he found ... "I happened, entirely by accident, to visit a Quaternary gravel pit in which were exposed the spectacular bones of mammoth, woolly rhinoceros and bison.  Looking at their sediment matrix I was amazed to find enormous numbers of equally spectacular, if somewhat smaller, insect r...

It is often claimed that the  Sun  is causing global climate change. The Sun  is  the source of the heat on the Earth, but  it has not suddenly become more active recently. The Sun may be going into a phase of lower activity - but that will not reverse global warming. When the Sun's energy arrives at the Earth, it travels through the air. Some is reflected back to space, but some hits the Earth and warms it. The warm Earth gives off  infrared radiation  with various wavelengths.   Some of those waves can pass back out of the air to space, but some are absorbed by certain gases in the air. The gases then re-emit the energy into the air. If there are more of those gases, less heat escapes into space, so the Earth warms. In the graph below, from the  Stanford Solar Center , carbon dioxide data comes from the Law Dome ice core in Antarctica, and from the observatory on Mauna Loa in Hawaii. The Earth h...

Heavy rainstorms caused devastating flooding across a 12-county region of West Virginia in late June 2016. Events like this are almost certainly made more frequent, and more intense, by global warming.  Climate scientists from around the USA  said  that the overwhelming scientific evidence shows that the warming of the planet’s atmosphere is increasing the occurrence of, and the seriousness of, heavy rains. Warmer air holds more water, leading to stronger and more frequent heavy precipitation events.  This is confirmed by research done by  a team of scientists of the Potsdam Institute for Climate Impact Research. They find the worldwide increase to be consistent with rising global temperatures, caused by greenhouse-gas emissions from burning fossil fuels.  Short-term torrential rains can lead to high-impact flooding.

Some people claim the current climate change has " natural causes ". They talk about the changes during the  'Ice Age' , thinking the current events must be natural as well. Scientists say that is not the case. The current situation is different. The things that caused the changes in the Ice Age are not exactly the same this time. The graph below shows that carbon dioxide in the air has increased and decreased over hundreds of  thousands of years. The  recent increase in carbon dioxide is much bigger and faster  than the natural changes. The low readings match with times called  'glacial stages'. During glacial stages, ice covered large areas of the Earth. The most recent glacial stage occurred between 115,000 and 11,500 years ago.  The peaks in the graph show times when carbon dioxide was high. Those times are called  'interglacial stages' .   Glacial and interglacial stages are linked to regular patterns in the movements of the...