ROCKY REX'S SCIENCE BITES

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...

According to the  Royal Society ....... If human emissions of CO 2  stopped altogether... .... it would take thousands of years for atmospheric CO 2  to return to ‘pre-industrial’ levels. " The climatic impacts of releasing fossil fuel CO 2  to the atmosphere will last longer than Stonehenge, " says  University of Chicago oceanographer  David  Archer. "Longer than time capsules, longer than nuclear waste, far longer than the age of human civilization so far." Why is that? It takes a long time for deep oceans to bury the carbon dioxide in ocean sediments.  Lifee on the abyssal sea floor (depths ranging from 4000-6000 m) near the Hudson Canyon off the coast of New Jersey. Photo taken using the Deep Submersible Research Vessel (DSRV)  Alvin's camera system.  Image courtesy of Deep East 2001, NOAA/OER. Surface temperatures would stay high for at least a thousand years. Humans would face  a warmer planet due to past and curre...

The  Arctic   includes an  ocean covered by sea ice. Arctic sea ice  melts back 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 graphs come from the US  National Snow and Ice Data Center. The NSIDC also publish this graph, which is normally updated every day. More graphs and other data are also available from the  Arctic Data Archive System , operated by the Japanese  Arctic Environmental Observation Center. The total volume of Arctic sea ice has declined dramatically over time. New research   shows the decline in Arctic sea ice area since 1850: Research suggests   the remarkable decline of   Arctic sea ice over  the last century is far beyond anything seen for a long time.  

The constellation  Gemini  features in  the winter sky. Castor and Pollux  are very bright  stars. Castor  is actually six stars in a complex system. Pollux  is a Red Giant star, with at least one planet. Gemini also contains a  star cluster  known as  M35 .

Orion's Belt points to the red star Aldebaran, and to the  Pleiades  star cluster.  The Pleiades can be seen without binoculars, even from light-polluted cities.  Also known as the Seven Sisters and M45, the Pleiades is an "open star cluster." The  Pleiades  contains over 3000 stars, is about 400  light years  away, and is 13 light years across.  The photograph also shows the blue reflection nebulae (gas clouds) that surround the stars.

In the Northern Hemisphere some of the stars of  Ursa Major  are easy to see on clear nights. They make a pattern sometimes called the Big Dipper or the Plough. Ursa Major  and  Ursa Minor  are the 'Great Bear' and the 'Little Bear'. The two brightest stars of Ursa Major are known as the  Pointers , because they point at the brightest star of Ursa Minor,  Polaris , the Pole Star. The Pole Star, or North Star, has always been used for navigation. Photographs show that as the Earth turns, Polaris is almost fixed in the centre of the turning star pattern. Like many stars , the stars of the Plough have Arabic names. One star,  Mizar , is actually a  double star. Alcor  probably orbits Mizar , taking around 750,000 years to complete one orbit. Some people with good eyesight can see Alcor and Mizar as two stars on a clear night. They can certainly be seen very easily with binoculars.

The constellation of  Orion  dominates the southern sky during winter in the Northern Hemisphere. The brightest stars of Orion have wonderful names. The Red Giant star  Betelgeuse  marks one shoulder, the other shoulder is marked by  Bellatrix . The three Belt Stars (left to right) are  Alnitak ,  Alnilam  and  Mintaka. The knees are marked by  Saiph  and the very bright  Rigel . Like many star names, they are of Arabic origin . The stars of Orion act as signposts to other stars seen at the same time of year. Orion's stars are good examples of some of the wide variety of types of stars.   The Sun is really rather small compared to many stars

Footprints  of many kinds of creatures have survived as  fossils  in rocks. This can be because they were quickly covered by volcanic ash, or layers of fine clay, preserving the details. These footprints were most likely made by  Australopithecus afarensis , an early human whose fossils were found in the same sediment layer. They were found at Laetoli in Tanzania. The Smithsonian Museum has a wonderful site about footprints found at Laetoli. Looking at much older rocks, footprints of  dinosaurs  can be used to find out all sorts of things about their lives. There are plenty of dinosaur tracks in Texas, for example . Dinosaur footprints can make an   interesting educational activity.

The  permafrost  of places like  Siberia  is not so permanently frozen any more. As it slowly melts, wonderful things are emerging, some frozen for tens of thousands of years. Baby mammoths  are sometimes found in an extraordinary state of preservation. "As the Earth warms, scientists worry that some of the carbon in permafrost could escape to the atmosphere as carbon dioxide or methane.  Increasing the amount of these gases in the atmosphere could make Earth's climate warm up even more." Arctic permafrost – ground that has been frozen for many thousands of years – is now thawing because of global climate change.  There are many effects of global warming, including melting permafrost, discussed in this useful document:  Physical effects of warming. The results of melting permafrost could be  disastrous and irreversible.

Scientists have   observed an increase in carbon dioxide’s greenhouse effect   at the Earth’s surface for the first time.   The graphs show carbon dioxide’s increasing greenhouse effect at two locations.  The first graph shows CO 2  radiative forcing measurements obtained in  Oklahoma .  The second graph shows similar upward trends in  Alaska . (Credit: Berkeley Lab) The researchers link this to rising CO 2  levels from fossil fuel emissions. Radiative forcing  measures how the planet’s energy balance is altered by atmospheric changes.  Positive radiative forcing  occurs when the Earth absorbs more energy from solar radiation than it emits as heat radiation back to space. “We see, for the first time in the field, the amplification of the greenhouse effect because there’s more CO 2  in the atmosphere to absorb what the Earth emits in response to incoming solar radiation,” says Daniel Feldman. Dr Feldman ...

Summer in the south, winter in the north. Seasons are caused by the tilt in the Earth's axis. Winter Solstice is the time of the longest night and shortest day. Many ancient monuments are lined up with the solstice, which suggests it was an important moment of the year for many cultures. One is  Maeshowe  on Orkney. Others include  Stonehenge  and  Newgrange . Winter solstice sunset at Stonehenge in the mid-1980s. Image via Wikimedia Commons.

Burning  fossil fuels  produces  carbon dioxide . Carbon dioxide emissions  need to be limited.   However, the potential carbon dioxide emissions contained in fossil fuel reserves are vast. So   it's not possible for all current fossil fuel reserves to be used,  if the Earth's warming is to be kept below 2 °C.  This huge excess quantity of fossil fuel is sometimes called the  'Carbon Bubble'. However, there are   major objections  even to the "two-degree limit" . Many say the number is simply too high. Archbishop Desmond Tutu has  pointed out   that a two-degree global average rise might result in Africa’s temperature rising as much as 3.5 degrees—a potentially disastrous change. Various scientific research projects have looked at what would happen if all the fossil fuels were burned. One project concluded: The Antarctic Ice Sheet stores water equivalent to 58 metres in global sea-level rise....

The chaotic nature of  weather  makes it unpredictable beyond a few days.  To predict the weather you need to know exactly what is happening in the atmosphere down to the smallest scale.  Climate  is the  average weather pattern  of a region over many years (usually a period of 30 years). Weather forecasts  depend on knowing exactly what is going on in the atmosphere, down to the smallest scales.  Climate forecasts  look for patterns over a longer time.  Will it be generally wetter in winter?   Will there be more heavy downpours? A paper  published in the journal  Science  in August 1981  made several projections regarding future climate change. The projections were rather accurate — and their future is now our present. "Potential effects on climate in the 21st century include the creation of drought-prone regions in North America and central Asia as part of a shifting of climate zones...

Farmers can put up with some bad weather, but  climate change  will make unusual events more likely. 20-30% of plant and animal species will be more likely to become extinct if the temperature rises by more than 1.5-2.5C. There will be big effects on farming from droughts and floods. The biggest effects will be seen first near the  Equator . Just  being near the Equator  makes it more difficult for countries to make economic progress. Hotter conditions affect how crops grow. Our agriculture is heavily reliant on  grasses  from the temperate regions. Corn, wheat, and rice  are all types of grass. The Tropics will expand as the world warms, so the world will find it harder to grow those important crops. People will  try to leave places  where they cannot produce enough food. Countries where  food prices  rise rapidly tend to become unstable, making  conflicts  more likely. Global w...

Earth's poles 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. The winter sea ice has increased by around 1 % over the last few decades. This is due to complex processes. It is linked to  melting of the land ice on Antarctica ….. H...