ROCKY REX'S SCIENCE BITES

Between about 20,000 and 5,000 years ago, Earth slowly changed from the frigid conditions of an  Ice Age , to the world on which our civilization has developed. As the  ice sheets  melted, colossal volumes of  water  flowed back into the oceans. The  pressures  acting on the Earth's crust changed as a result.  The  weight of ice  on the continents was reduced, and the rising seas put  extra water pressure  on the seafloors. In response, the  crust  moved up and bent, creating extra volcanic activity, increased seismic shocks and giant landslides. So if we continue to allow greenhouse gas emissions to rise unchecked, causing serious warming, will our planet's crust react once again? In Alaska, climate change has pushed temperatures up by more than 3 degrees Celsius in the last half century, and  glaciers  are melting at a staggering rate, some losing up to 1 kilometre in thickness in the last 100 years.  The reduced weight on the crust beneath is allowing  faults  to

Hurricanes, cyclones, and typhoons are all the same weather phenomenon. We use those different names for these  tropical storms  in different places.  In the Atlantic and North-East Pacific, the term  “hurricane”  is used. Image of Hurricane Patricia tweeted by  astronaut Scott Kelly . In the North-West Pacific a tropical storm is called a  “typhoon” , and  “cyclones”  occur in the South Pacific and Indian Ocean. Three strong tropical storms  (Kilo ,  Ignacio , and  Jimen a) ,  formed in the Pacific in 2015.  On Sunday 30th August, all of them were a category 4.  This was the first time the north-eastern Pacific had seen three category 4 hurricanes at the same time. Multiple cyclones in the Pacific Ocean in 2015 Tropical storms  can’t form outside the tropics - water temperatures are too cold. Sea surface  temperature  must be at least 27 ° C , and this temperature is actually required to a depth of at least 50  m .  The warm tropical atmosphere heats up the water at th

Marlin  can hunt in water a half mile down, and sailfish often dive deep too. In more and more places around the world, ocean predators are sticking near the surface. Why? Warming temperatures are  sucking oxygen out of waters  even far out at sea, making enormous stretches of deep ocean hostile to marine life. New research  shows that this problem is getting worse. Vast stretches of the ocean interior  suddenly lost oxygen  during the transition out of the last  glacial stage , between 17,000 and 10,000 years ago.  This event was the most recent example of large-scale global warming. There are other examples in the geological record, including the  Zechstein Sea.

This graph shows how  carbon dioxide  has increased and decreased over hundreds of thousands of years. The low readings match with times called ' glacial stages '. During glacial stages,  ice  covered large areas of the Earth. The peaks in the graph show times when carbon dioxide was high, matching times called ' interglacial stages '. The most recent glacial stage occurred between about 115,000 and 11,500 years ago.   The  last interglacial period  occurred before it, from around 130,000 to 115,000 years ago. It's official international name is the  Eemian,  but it has other names in specific places. Climate information from that time is particularly useful. During that time,  temperatures  on earth were higher at the poles than they are now.  The  sea level  was between five and nine metres higher than current levels, because of the melting of ice in  Greenland  and  Antarctica . In the UK, t his last interglacial period is called the

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 Switzerland, the dismal summer of 1816 led to

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 transports more water than "all the world's rivers combined," according to the National Ocea

Oil is a  fossil fuel . It was formed from chemicals from ancient living things. To make the chemicals in oil, the  temperatures  and  pressures  needed to be just right. The oil (and gas) will only stay in the reservoir if there are  suitable structures  in the rocks: The carbon compounds from the plants and animals have been trapped for hundreds of millions of years. They have been burned to make carbon dioxide in a very short time. The amount of carbon dioxide in the air has changed very quickly. Diagram of how oil is made Source:  Library and Archives Canada © Library and Archives Canada

What is the worst-case scenario for climate change? The geological record shows that when the atmosphere suddenly changes, there are big effects on living things. 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. Chongqing Special Administrative Region (SAR) in central China, showing a hillside that includes rocks crossing the end-Permian extinction event and the Permian-Triassic boundary. Researchers have found evidence of a compound called fly ash, one of the products of coal combustion, in rocks laid down just before this extinction event.  A large amount of coal had been burned over a period of tens of thousands of years. The  coal was burned by volcanic eruptions  that happened in Siberia,

W hy can’t recent  climate change  just be an effect of 'natural causes'? There have been climate changes in the past 2000 years. People talk about times called the  Medieval Warm Period  and  the  Little Ice Age . Careful research  has shown that the current temperature is warmer than the Medieval Warm Period - temperatures between 1000 and 1100 AD were probably similar to parts of the 20th century, but 21st century temperatures are already warmer. The Medieval Warm Period may not even have been a global event -  glaciers on Baffin Island   were no smaller during that time. A particularly cool period is often called the   Little Ice Age. However,   the name "Little Ice Age" is now regarded by some scientistsas misleading. The best estimate of the drop in temperature is, at most, 0.5°C,  compared to the temperature decreases in "real" ice ages of about 8°C.   Also, the "Little Ice Age" only lasted for 500 years at most, compared to the 2

Some people confuse 'climate' with 'weather' - but i f 'climate' and 'weather' are the same, why would there be two words? Other people say "We call climate change 'winter' and 'summer'...."   What does the word ' climate ' mean? It normally means  the average of conditions over 30 years . Climate  normally means 'an average over 3 conventional decades'. A  conventional decade  is, for example, 2001-2010, or 1961-1970. So ..... 3 full, conventional decades......such as 1981 to 2010. For example .... average temperature in Ireland, 1961-1990: And another example -  ' A verage temperature 1951-1980' The definition of 'climate' goes back at least 100 years. So if we are discussing  climate change , that is what 'climate' means. But in recent times, there has been a lot of variation in global temperatures. So it can be useful to look at  single conventio

Carbon dioxide  levels in the atmosphere are rising. This graph showing the data is called the  Keeling Curve . The small up-and-down pattern is caused by changes during each year -  in the summer in the northern hemisphere, there is more photosynthesis which causes CO2 levels to fall. The Keeling Curve is named after the scientist who first produced accurate measurements of carbon dioxide in the air -  Charles David Keeling.     Charles David Keeling in the lab. Keeling's collection of data began in 1958. Concentration is measured in  p arts  p er  m illion (ppm) March 2015 was the first time for hundreds of thousands of years that CO2 exceeded 400 ppm for a whole month. Ice core data  shows humans have never breathed air containing so much CO2. Since Keeling began recording, CO2 has risen from 318 ppm to 400 ppm... a rise of around 25%.   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