ROCKY REX'S SCIENCE BITES

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 ...

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...

According to the US National Oceanic and Atmospheric Administration (NOAA)  the combined global average temperature over the land and ocean surfaces for March 2017 was 1.05°C above the 20th century average of 12.7°C. This was  the first time the monthly temperature departure from average surpasses 1.0°C in the  absence of an El Niño episode  in the tropical Pacific Ocean.

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. Ice shelves  around Antarctica are also affected by global warming. For a useful comparison of Antarctic and Arctic sea ice follow this link…… Arctic vs Antar...

There were some very unusual weather events in 2010, which may be a warning of future effects of climate change. Each time there are  extreme weather events , people debate "Is there a link to climate change?" It might be hard to prove in many cases. Some recent events, however, are extraordinary. The phrase  'weather on steroids'  has been used to describe these events. In 2010,  China  and  Brazil  had serious droughts, and in the first part of the year the Northern Hemisphere warmed fast, melting the winter snow cover very quickly. The picture shows the dried-up  River Negro  in Brazil, with a bridge in the distance.   But the biggest events were  the  heatwave in Russia  and the  flooding in Pakistan . In  Pakistan ,  Government officials said that from  July 28 to Aug. 3, parts of Khyber Pakhtunkhwa province recorded almost  12 feet (3.6 metres) of rainfall  in one week .  ...

Around 34 million years ago, at the  Eocene-Oligocene Transition  (EOT), the Earth was undergoing a period of global cooling.  Antarctica  changed from a green forested continent to the land of ice we know today.  The cooling was partly caused by  declining atmospheric carbon dioxide  levels, but it also coincides with changes in the geography of the Southern Ocean. This is an image of how this ancient world might have looked,  created recently by  Alan Kennedy  of the University of Bristol - Around 55 million years ago, CO2 levels rose during the  Paleocene-Eocene Thermal Maximum   (PETM). Weathering of the newly-building  Himalayas  caused CO2 levels to begin to fall. CO2 in rain makes a weak acid, which causes chemical weathering (especially of carbonate rocks like limestone, but of other rocks as well). Rivers carry the carbon compounds down to the oceans, where various processes (such as the fo...

Animals  are reacting to climate change very quickly. Some move to higher places,  others move north or south. Dragonflies  love warmer temperatures. UK dragonflies have mainly stayed in the south of the country, until recently. Ruddy Darter ( Sympetrum sanguineum ) Since 1980, 34 out of the 37 British species of dragonfly have expanded their range northwards by an average of 74km. That is over 2km per year..... nearly 6 metres per day. For example, the  ruddy darter  ( Sympetrum sanguineum ) and the  hairy dragonfly , ( Brachytron pratense ), have moved into north-west England.  This is evidence that the UK’s climate is growing warmer. "So much has happened to  dragonflies  in Britain since the 1990s that there is a most compelling case for the Government to adopt them as indicators of climate change", said  Steve Brooks . He is a London Natural History Museum research entomologist, with a special interest in the...

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 m...