With the Rio+ 20 conference on sustainable development now over, it remains
unclear how much attention policymakers, businesses and the public paid to
scientific analyses of climate change. A question also remains as to how
impartial, objective and direct scientists were in presenting their evidence;
politicians may well have left Rio without understanding the viability and
implications of proposed lowcarbon pathways.
We urgently need to acknowledge that the development needs of many countries
leave the rich western nations with little choice but to immediately and
severely curb their greenhouse gas emissions1, 2. But academics may again have
contributed to a misguided belief that commitments to avoid warming of 2 C can
still be realized with incremental adjustments to economic incentives. A carbon
tax here,
No. 1: The planet is warming, from North Pole to South Pole. Since 1906, the
global average surface temperature has increased by more than 1.6 degrees
Fahrenheit (0.9 degrees Celsius)—even more in sensitive polar regions. And the
impacts of rising temperatures aren’t waiting for some far-flung future–the
effects of global warming are appearing right now. The heat is melting glaciers
and sea ice, shifting precipitation patterns, and setting animals on the move.
No. 2: Many people think of global warming and climate change as synonyms, but
scientists prefer to use “climate change” when describing the complex shifts now
affecting our planet’s weather and climate systems. Climate change encompasses
not only rising average temperatures but also extreme weather events, shifting
wildlife populations and habitats, rising seas, and a range of other impacts.
All of these changes are emerging as humans continue to add heat-trapping
greenhouse gases to the atmosphere.
No. 3: Scientists already have documented these impacts of climate change:
Ice is melting worldwide, especially at the Earth’s poles. This includes
mountain glaciers, ice sheets covering West Antarctica and Greenland, and Arctic
sea ice. In Montana's Glacier...
The planet is warming, from North Pole to South Pole. Since 1906, the global
average surface temperature has increased by more than 1.6 degrees Fahrenheit
(0.9 degrees Celsius)—even more in sensitive polar regions. And the impacts of
rising temperatures aren’t waiting for some far-flung future–the effects of
global warming are appearing right now. The heat is melting glaciers and sea
ice, shifting precipitation patterns, and setting animals on the move.
Scientists already have documented these impacts of climate change:
Ice is melting worldwide, especially at the Earth’s poles. This includes
mountain glaciers, ice sheets covering West Antarctica and Greenland, and Arctic
sea ice. In Montana's Glacier National Park the number of glaciers has declined
to fewer than 30 from more than 150 in 1910.
Much of this melting ice contributes to sea-level rise. Global sea levels are
rising 0.13 inches (3.2 millimeters) a year, and the rise is occurring at a
faster rate in recent years.
Rising temperatures are affecting wildlife and their habitats. Vanishing ice has
challenged species such as the Adélie penguin in Antarctica, where some
populations on the western peninsula have collapsed by 90 percent or more.
As temperatures change, many species are on the move. Some butterflies, foxes,
and alpine plants have migrated farther north or to higher, cooler areas.
Precipitation (rain and snowfall) has increased across the globe, on average.
Yet some regions are experiencing more severe drought, increasing the risk of
wildfires, lost crops, and drinking water shortages—including mosquitoes, ticks,
jellyfish, and crop pests—are thriving. Booming populations of bark beetles that
feed on spruce and pine trees, for example, have devastated millions of forested
acres in the U.S.