ROCKY REX'S SCIENCE BITES

Carbon dioxide is always in the atmosphere as part of the Earth's  carbon cycle. The global carbon cycle transfers carbon through the Earth’s different parts -  the atmosphere, oceans, soil, plants, and animals.  So carbon moves around — it flows — from place to place. Carbon dioxide (CO 2 ) is the main  greenhouse gas  emitted through human activities.  Human activities  are changing the carbon cycle. First, by adding more CO 2  to the atmosphere, mainly by  burning fossil fuels . Also by changing the ability of  natural sinks , like forests, to remove CO 2  from the atmosphere.  Human-related emissions are responsible for the increase that has occurred in the atmosphere since the industrial revolution.   The  carbon sinks,  on land and in the oceans, have responded by increasing the amount of carbon they absorb each year. Carbon sinks cope with  about half  of human greenhouse ga...

Iceland lies on the  Mid-Atlantic Ridge , which is why it has volcanic activity. Iceland also has  ice caps  and  glaciers . Iceland is one of the fastest-warming places on the planet  – as much as four times the Northern Hemisphere average.  The glaciers that cover more than 10 percent of the island are losing an average of 11 billion tons of ice a year.                 Iceland glacial meltwater - photo Tom Harding The water melting from Iceland's glaciers would fill 50 of the world's largest trucks every minute. Parts of Iceland are rising as the ice caps melt,  reducing the weight on the Earth's crust. The thinning of the ice caps reduces the pressure on the rocks. Geologists know lower pressure from above makes volcanoes erupt more easily. Lower pressure allows volcanic gases to expand, and mantle rocks melt more easily at lower pressure as well. So more magma can rise into the vol...

2016 was the warmest year in  NOAA 's 137-year series.  This is the third consecutive year a new global annual temperature record has been set.  All 16 years of the 21 st  century are included in the seventeen warmest years in the modern record (1998 is currently the eighth warmest.)  The five warmest years have all occurred since 2010. It is increasingly likely the Earth is now warmer than at any time since the Eemian Interglacial, over 115,000 years ago. The Eemian was warmer than the  Holocene  because of higher insolation. Insolation refers to the amount of solar energy received per unit time at any one location, and it was higher  due to astronomical cycles.

Atmospheric carbon dioxide concentration  is now around 400 parts per million (ppm). It last reached similar levels during the  Pliocene , 5.3-2.6 million years ago.   Outcrop of Middle Pliocene diatomaceous lake beds at Ledi Geraru, northern Afar region of Ethiopia. (photo: Roy Johnson.) In the middle Pliocene,  the concentration of carbon dioxide in the air ranged from about 380 to 450 parts per million.   During this period, the area around the North Pole was much warmer and wetter than it is now. Summer temperatures in the Arctic were around 15 degrees C , which is about 8 degrees C warmer than they are now. Global average temperatures were 2-3°C warmer than today. Sea level was up to 40 metres higher than now. Of course, there were no modern humans at that time. Hominids of the Pliocene Nor was there a  global system of food supply   relying on stable climates for agriculture. For more on research into the cl...

Arctic permafrost – ground that has been frozen for many thousands of years – is now thawing because of global climate change. “The release of greenhouse gases resulting from thawing Arctic permafrost could have catastrophic global consequences,” said  Dr. Max Holmes, a Senior Scientist at the Woods Hole Research Center (WHRC). G reenhouse gas es and permafrost.   Graphic by John Garrett. Thawing permafrost releases greenhouse gases (carbon dioxide and methane) into the atmosphere, which accelerate climate change, which in turn cause more thawing of the permafrost.  This may be a fairly slow process, and there is a lot more research to be done in this area. Some scientists fear that this potentially unstoppable and self-reinforcing cycle could produce a dangerous "tipping point".

Oceania  is a region made up of thousands of  islands throughout the Central and South  Pacific Ocean.   It includes Australia, the smallest continent in terms of total land area. Many of the nations in Oceania are  Small Island Developing States (SIDS). Many scientists say that Oceania is more vulnerable than most parts of the Earth to climate change, because of its climate and geography.  The heavily coastal populations of the continent’s small islands are vulnerable to flooding and erosion  because of  sea level rise.   An international team of researchers  has produced this graph of ocean levels, for a period of time going back to around 500 BC.  Five of the Solomon Islands have been swallowed whole by rising sea levels between 1947 and 2014.  "It’s a perfect storm,” says  Simon Albert  of the University of Queensland. “There’s the background level of global sea-level rise, and then the add...

Heat can affect things without causing a temperature rise. Extra heat can be used in ‘ changing state ’ instead of raising temperature. A change of state could be … a  solid  melting to a  liquid .  Or a  liquid  evaporating to a  gas . So  heat is needed to change ice at zero degrees C to water at zero degrees C. And to change water into water vapour….. without raising the temperature. Scientists call the heat used to change state  latent heat. Also, there are natural variations in the global climate,  El Nino  events being the ones that affect world temperature the most. The opposite to 'El Nino' is 'La Nina', a cooling effect. If global temperatures are plotted on a graph in a way that shows these variations, it makes the overall warming trend very obvious. Every La Nina year since 1998 has been warmer than every El Nino year before 1995. As the Earth warms, each El Nino event 'rides' on a higher base-...