President Barack Obama has some tough choices to make about energy and the environment and he’ll likely use Tuesday’s new climate report to make some of them.
The third National Climate Assessment, an update from 2009, is a detailed 1,300 page report that was compiled by 13 departments and agencies ranging from the U.S. Department of Agriculture to NASA and includes contributions from more than 240 scientists. The White House commissioned the report as part of Obama’s Climate Action Plan.
The report warns of a warming planet, shrinking glaciers and a dire climate situation that may soon be unfixable. In other words, the scientific report is nothing new.
But it is significant for the president on some key issues, notably the Keystone XL pipeline. Additionally, after a recent go-ahead by the Supreme Court, Obama is expected to unveil new and controversial rules to curb power plant emissions of carbon dioxide.
The findings of this climate report might be the tipping point for Obama to make a decision in favor of environmentalists on both issues.
Here are the top 9 nuggets to know from the report explained:
1. Temperatures did rise, are rising and will likely continue to rise
According to the report, average temperatures in the U.S. increased by 1.3 to 1.9 degrees since the late 1800s. Most of the changes started happening in 1970. Although the country has witnessed both abnormally cold years as well as hot and dry ones, a rising climate doesn’t affect temperatures uniformly. The report found that the nation’s past decade has been the warmest on record.
The colors on the map show temperature changes over the past 22 years (1991-2012) compared to the 1901-1960 average for the contiguous U.S., and to the 1951-1980 average for Alaska and Hawai’i. The bars on the graph show the average temperature changes by decade for 1901-2012 (relative to the 1901-1960 average). The far right bar (2000s decade) includes 2011 and 2012. The period from 2001 to 2012 was warmer than any previous decade in every region.
2. Ice caps and glaciers are melting—really
The decline in arctic sea ice is unprecedented in historical records. Ice thickness has decreased by more than 50 percent from between 1958-1976 and 2003-2008. The loss of ice not only threatens coastal communities where they will see the sea-level rise as a result, but also marine mammals such as polar bears and seals that need the ice to live. Alaska Native coastal communities also rely on the ice.
Image on left shows Arctic minimum sea ice extent in 1984, which was about 2.59 million square miles, the average minimum extent for 1979-2000. Image on right shows that the extent of sea ice had dropped to 1.32 million square miles at the end of summer 2012.
3. It’s getting wetter, in some places
The average annual precipitation around the U.S. has increased in recent decades. The hardest hit areas are the Midwest (9 percent), Northeast (8 percent) and the Southern Great Plains (8 percent).
The colors on the map show annual total precipitation changes for 1991-2012 compared to the 1901-1960 average, and show wetter conditions in most areas. The bars on the graph show average precipitation differences by decade for 1901-2012 (relative to the 1901-1960 average). The far right bar is for 2001-2012.
4. It’s also getting hotter, in some places
It’s probably no surprise that the amount of annual heat waves are on the rise. The number of heat waves between 2011 and 2012 are nearly triple the long-term average. The amount of prolonged extreme heat—abnormally high temps that last for multiple months—is unprecedented.
Map shows numbers of days with temperatures above 100°F during 2011. Black circles denote the location of observing stations recording at least one such day. The number of days with temperatures exceeding 100°F is expected to increase. The record temperatures and drought during the summer of 2011 represent conditions that will occur more frequently in the U.S. as climate change continues.
5. Fossil fuels are the top global warming offender
The report found that natural factors cannot explain the observed warming of the planet. Although historically, naturally-occurring factors such as volcanoes, sun energy and variations in atmosphere gases greatly contributed to some climate change, since the industrial revolution human activity has increased the effect—and become the leading cause of it.
Increases in concentrations of these gases since 1750 are due to human activities in the industrial era. Concentrations are parts per million (ppm) or parts per billion (ppb), indicating the number of molecules of the greenhouse gas per million or billion molecules of air.
6. Extreme weather events cause people to move
When weather causes critical systems to fail, large portions of the population migrate away from the site to find new places to live. Hurricane Katrina is a big example, as is what happened following Hurricane Sandy. The amount of mass diasporas away from a region affected by climate has the potential to increase with global warming.
This map illustrates the national scope of the dispersion of displaced people from Hurricane Katrina. It shows the location by zip code of the 800,000 displaced Louisiana residents who requested federal emergency assistance. The evacuees ended up dispersed across the entire nation.
7. We are using air conditioning more, heat less
Less energy has been required to heat buildings in the winter compared to the average for 1970-2000. This is explained by an overall increase in annual temperatures.
Figure shows observed increases in population-weighted cooling degree days, which result in increased air conditioning use, and decreases in population-weighted heating degree days. Cooling degree days are defined as the number of degrees that a day’s average temperature is above 65ºF, while heating degree days are the number of degrees a day’s average temperature is below 65ºF.
8. Our water is at risk
The West Coast drought has been headline news. The study says similar water shortages will increase over time. Climate change is projected to reduce water supplies in areas of the country where precipitation is projected to decline — and even in areas where rain is expected to increase. The study found that compared to 10 percent of counties today, by 2050 about 30 percent of counties will be at high or extreme risk of water shortages.
Numbers of counties are in parentheses in key. Projections assume continued increases in greenhouse gas emissions through 2050 and a slow decline thereafter.
9. Less water and more heat means less food
Because of the sensitive relationship between climate and crops, the increased effects of global warming are expected to threaten U.S. agriculture. Temperatures aren’t the only variable. Increased or decreased temps may also trigger extreme weather events and unforeseen pest and pathogen surges.
Crop yields are very sensitive to temperature and rainfall. They are especially sensitive to high temperatures during the pollination and grain-filling period. For example, corn (left) and soybean (right) harvests in Illinois and Indiana, two major producers, were lower in years with average maximum summer (June, July, and August) temperatures that were higher than the 1980-2007 average. Most years with below-average yields are both warmer and drier than normal.
Note: Unless otherwise noted, all graphs, numbers and quotes are from the National Climate Assessment.