Sea ice can be described as frozen seawater floating on the surface of the polar oceans. It does not include icebergs or ice shelves, as these are originating from glaciers, rather than sea water. Sea ice becomes thickest and most widespread over the respective winter months in each hemisphere, covering the oceans around the Arctic and Antarctic with millions of square kilometres of ice. It melts when the seasons change, but in the Arctic large areas remain covered all year around, while Antarctic sea ice melts away over the summer in the southern hemisphere.
Renewable energy is defined as ‘energy from a source that is not depleted’. Main sources include biomass, hydropower, wind, biofuels, solar, heat pumps, biogas, geothermal, and marine (such as tidal power). Data by the International Energy Agency sees the share of renewable energy in global power generation at 22 per cent in 2013, with an estimated increase to 26 per cent by 2020 as a result of supportive policies by a large number of governments.
Tropical cyclonic systems are generally referred to as tropical storms. They are better known by their regional names, such as hurricanes in the Caribbean and North America, or typhoons in parts of Asia. They form near the equator over larger bodies of warm waters that evaporate from the ocean surface and fuel these emerging storm systems. Their strong winds and heavy rainfalls frequently become part of our news as they often put large numbers of human livelihoods at risk.
Recent studies show that the number of tropical cyclones (as well as tropical cyclone intensity) over the past decades has increased. Tracks of tropical storms collected over a longer period can indicate where such storms occur most frequently. The records used in this issue’s visualisation covers data from 1945 to 2008.
Recent figures released by the NASA as well as the British Met Office and NOAA confirm that 2015 was the hottest year ever recorded. In addition, the period of the past five years was also the warmest in recent times. The following map animation visualises a data series by NASA’s Goddard Institute for Space Studies (GISS) that depicts “how much various regions of the world have warmed or cooled when compared with a base period of 1951-1980. They show temperature anomalies, or changes, not absolute temperature. (The global mean surface air temperature for that period was estimated to be 14°C or 57°F.)” It uses an equal population project in form of a gridded cartogram so that the underlying temperature anomalies can seen in relation to the global population distribution:
The effects of humans on the global environment are perceived to be so significant by some scientists that they argue the onset of industrialisation (in the eighteenth century) has been a major driving force in environmental change on a par with the forces of nature. It is this rapid impact that has led some geologists to unofficially name (but not, as yet, officially recognise) this recent period of the earth’s history (from around 1760-onwards) as the Anthropocene (roughly translating as the era – or epoch – shaped considerably through the actions of humanity).
Gridded population cartogram displaying the topography of the world in relation to the population distribution (click here for larger version)
“There is no planet B”. This slogan has become widely mentioned recently in relation to COP21, the United Nations conference on climate change in Paris. The slogan highlights that the debate about climate change relates to much more than simply a changing climate. The underlying processes have a lot to do with our lifestyles and the related patterns of consumption and waste which cause severe damages to the environment (including the global climate). Carbon emissions are therefore one major trigger of climate change, but are also an effect of our unsustainable ways of life. The ecological footprint shown in the following map is a measure that looks at the impact that humanity has on our planet: