The Greenhouse Trust

CLIMATE CHANGE -  MYTHS & ANSWERS

CO₂ ISN’T A GREENHOUSE GAS

Probably the easiest to answer and the earliest piece of climate science demonstrated by John Tyndall in the 1860s. Fill a plastic bag with CO₂, shine a lamp on the bag and compare the temperature of a bag filled with air given the same treatment.

WHEN THE CLIMATE CHANGED IN PREHISTORIC TIMES, THE WARMING CAME FIRST, THEN THE CO₂ ROSE AFTERWARDS

Ancient ice cores, tree rings, coastlines and the ocean’s depths provide evidence of how temperatures, sea levels, and the amount of CO₂ in the air have changed over the last few tens of millions of years.

The Earth has swung between colder and warmer periods over the aeons (see Figure 1). These huge changes were initially triggered by tiny fluctuations in the Earth’s temperature – the sun might go though a slightly warmer or cooler phase, or the Earth’s orbit vary enough to move the planet closer or further from the sun. This change, taking place over hundreds of thousands of years would transform into rapid change, switching the planet from cool to warm or vice versa.

As the planet warms, CO₂ and methane are released from plants, soils and oceans. The release of these gases creates a greenhouse effect, which leads to warming and more release of CO₂ and other gases, and so on.

MANY SCIENTISTS DON’T AGREE WITH THE CONSENSUS ON CLIMATE CHANGE

In 2009, Doran and Zimmerman of the American Geophysical Union undertook a study entitled ‘Examining the Scientific Consensus on Climate Change”, which showed that  97% of published climate scientists believe that human activity is changing the climate. There is disagreement about the precise effects, but the fact that it is happening, and it is very serious, is not disputed.

THE WORLD ISN’T REALLY WARMING UP

Figure 2 – shows the global air temperature over the last 150 years.

Figure 3 – adds in the ocean temperature since 1950. Ocean heating is by far the most significant. The top ten hottest years in recorded history have all happened in the last twelve years.

Meanwhile, cyclical weather patterns like El Nino and La Nina move heat back and forth between the oceans and the air in an irregular fashion – a major reason why atmospheric temperatures aren’t rising in a clear straight line.  For example, a strong El Nino shifted a lot of heat from the seas into the air in 1998, causing a spike in air temperatures. When temperatures in the following years reverted back, climate deniers claimed global warming had ‘stopped’.

GLOBAL WARMING IS CAUSED BY THE SUN

The sun does go through periods of increased activity. However, all the extra sun activity of the last 150 years only accounts for a small amount of warming. Sun activity has remained roughly level since the 1960s.

Figure 4, shows that the sun has in fact been cooler than usual since 2003.

GLOBAL WARMING IS CAUSED BY COSMIC RAYS/SOMETHING ELSE

The ‘cosmic rays’ idea comes from a handful of largely discredited scientific papers about the possible effect of cosmic rays on cloud formation. Whilst this is an important scientific principle, the
evidence can be robustly challenged, this is where climate deniers maliciously create havoc. Try suggesting to someone that the
reason that leaves fall off trees in the winter is because the squirrel in your garden pulls them all off, and you get some idea of how far fetched these ideas really are

THE ANTARTIC IS GROWING, NOT SHRINKING

This is true for certain areas of Antarctica, and actually gives us MORE evidence for global warming. Increased evaporation caused by higher temperatures has led to more snowfall in some parts of Antarctica and thus thicker ice cover in these areas (usually inland). Closer to the sea (which is warming faster than the air) the ice is retreating dramatically.

IT’S NOT A CONCERN THAT SHIPS CAN GET THROUGH THE ARCTIC NORTHWEST PASSAGE. IT WAS OPEN IN THE EARLY 1900s AS WELL

It’s true that the Northwest Passage (linking the Atlantic and Pacific Oceans above North America) – was first navigated by Roald Amundsen in 1903. However, it took him three years and the passage was completely impassable for most of the year. The Arctic ice has melted to the extent that it is now an economic shipping route, which has triggered sovereignty disputes between Canada and other countries.

CLIMATE CHANGE MEANS UK WEATHER WILL BE BETTER

Warmer temperatures might mean that some parts of Europe will be less cold during the Winter, so fewer people will die of Cold, but the other side of the coin is higher temperatures in the Summer will also kill vulnerable people (especially in the major cities that have not been designed for heat-waves). Small local pockets of positive effects are hugely outweighed by the negative. Even if climate change makes some places more comfortable to humans, will we all be able to move to the these places and where will all the people displaced by storms, floods, droughts and sea level rise move too?