Radiant energy from the sun falls on the Earth; some of this energy is absorbed by the planet and its atmosphere. Some of the energy is radiated back into space. The balance between the absorbed and radiated energy determines global temperature. This balance is changed by a number of factors - the intensity of the solar energy, cloud reflectivity, the absorption of energy by various gases or surfaces.
The reflectivity of the Earth’s surface (the albedo) influences the amount of light energy that is reflected back into space. Snow has a high albedo, that is, it reflects much of the light back out into space. Dark objects (like conifer plantations) reflect less light / radiation and absorb more thereby trapping heat that would otherwise be reflected back into space. The amount of energy that is ‘retained’ is also influenced by the presence of particular gases in the atmosphere - the so-called 'greenhouse gases', notably carbon dioxide and methane. The amount of carbon dioxide in the atmosphere has increased dramatically from 280 ppm during the 10,000 years up to the mid-18th century to 415 ppm (as of 2019). This increase has certainly contributed to the changes in climate that we have witnessed in recent years - extreme weather events such as heat waves and flooding. Read more...
Globalisation is the process by which economies and cultures are drawn together; they become more inter-connected through the flow of trade, capital, people and technology. This has occurred in part due to the rapid growth of air travel, container shipping etc. so that there are now massive movements of people and goods (both raw and manufactured). One positive aspect of globalisation is that we have access to foods and materials from all over the world. A downside is that disease, parasites and pests can ‘hitch a ride’ with people or materials and goods as they move across the world. Plants and animals can also change their geographical range / distribution as a result of climate change. The woodlands blog has outlined some of the problems associated with various ‘alien or invasive’ species, for example,
Dendrochronology seeks to gather information from the annual rings of trees, dated to their year of formation. As trees age, they form new distinctive rings, outward from the centre, and each year a circle of new, dead wood is formed (by the cambium) around the trunk of most trees. The annual rings form because the water conducting xylem vessels or early wood formed in late spring and early summer (when growth is rapid) are wider and lighter than those formed in late summer and early autumn, which are narrower and darker (sometimes called the late wood). A light and dark ring together constitute one year’s growth. In winter, there is no growth.
Trees and their annual rings are essentially long term recording devices that ‘house’ information about climatic variations, past climates and ecosystems; they can even offer insights into historical events. From an annual ring, it is possible to extract information about precipitation, temperature and other climate data about that year. Read more...
A number of initiatives both national and inter-national have focused on the possibility of large scale tree planting as a means of reducing the effects of climate change and keeping global warming below the critical 2oC threshold. Indeed, some researchers have estimated that restoring and creating forests could reduce atmospheric carbon dioxide levels by 25%, ‘sucking out’ some (extra) 200 gigatonnes of CO2 and locking it away in wood.
However, there are problems with this approach.
- Some estimates suggest that human activities have added a massive 600 gigatonnes of CO2 to the atmosphere over the millennia
- Restoring or establishing forests is not a ‘simple matter’ of planting some trees (albeit millions of them); there are technical and financial challenges (see * below, for exmple).
The results of the Big Butterfly Count are in and have been analysed; one of the most interesting observations is that the migratory butterfly - the painted lady - was here this summer in amazing numbers. There were 30 times as many here this summer as compared to 2018; indeed nearly half a million were recorded across the U.K. The last time such numbers were seen in the UK was some ten years ago - in 2009, and before that in 2003 and 1996..
Each year, successive generations of Painted Ladies move northwards from Africa to breed in central and northern Europe during the summer. Read more...
In early Spring this year, both Norway and Sweden reported wild fires in their forests, due in part to a run of dry weather. More recently, fires have been reported in many parts of the world - particularly in the Amazonian Forest, parts of Africa, Siberia, Canada and even within the Arctic Circle.
A few years back, the Russian authorities initiated a policy of allowing remote forest fires to burn - unless the trees / areas were of economic importance. However, the fires this summer affected thousands of square miles of boreal forest and strong winds spread the smoke and ash across the country; it affected cities such as Novosibirsk and Krasnoyarsk (each home to a million people). Read more...
Twelve thousand years ago (during the late glacial maximum) massive ice sheets and glaciers extended across much of the world. Then, the climate began to warm and about ten thousand years ago, our landscape started to look very different from today - not just because there were no roads, towns or cities but because the newly exposed land was being colonised by plants, trees, animals – and lastly by people.
The forests and woodlands that slowly developed in the post Ice Age period were different to the forests and woodlands that we see today. The land was colonised (at this time) by the plants and animals that lived on ‘the edge of the ice’. Read more...
Declining bee populations in Europe have caused alarm in recent years and the decline has been attributed to a multitude of factors / causes, for example :-
- Climate change
- Pesticides - especially neonicotinoids
- Varroa mites