Monday, February 11, 2019

2018 a Warm and Wet Year in the United States

On February 6th 2019 NOAA announced that 2018 was the fourth warmest year on record ranking just behind 2016 (the warmest), 2015 (the second warmest) and 2017 (the third warmest). The land surface temperature was 2.02 degrees above average, both the fourth highest on record While the globally averaged sea surface temperature was 1.19 degrees F above average. 
from NOAA
However, the average temperature for the contiguous U.S. was 53.5 degrees F (1.5 degrees above average). Most of the Northern Plains and Upper Midwest experienced near-normal temperatures, while the west of the Rockies and across the coastal Southeast was warmer than average. Overall, 2018 was the 14th warmest year on record. The United States has now had 22 consecutive warmer-than-average years.

Record high annual temperatures were experienced elsewhere on the globe- across much of Europe, New Zealand, and parts of the Middle East and Russia. No land areas were record cold for the year. The diagram below from NOAA shows the full picture of earth’s annual average temperature.

As most of you know, in the U.S., last year’s weather story was more about wetness than heat. Precipitation for the contiguous U.S. averaged 34.63 inches (4.69 inches above average), the third wettest year in the 124-year record. Here in my corner of Virginia total precipitation was almost 71 inches in my yard. I know this because I am a member of the Community Collaborative Rain, Hail and Snow Network known as CoCoRaHS, a non-profit, community-based network of volunteer citizen scientists working together to measure and map precipitation (rain, hail and snow).

Extreme weather events were attributed to the changing climate. In 2018, the U.S. experienced 14 weather and climate disasters, each with losses exceeding $1 billion and in all totaling around $91 billion in damages. Both the number of events and their cumulative cost ranked fourth highest since records began in 1980. Extreme event attribution seeks to determine whether climate change altered the likelihood of occurrence of a given extreme event. A long-term, high-quality records and a computer model capable of producing a realistic simulation are being used to assess the influence of climate change on extreme rainfall, drought, wildfires etc. Currently, scientists a better able to detect the influence of human-caused global warming on heat waves and, to a lesser extent, heavy rainfall events than our ability to detect its influence on tornadoes or hurricanes. Scientists look to be able to quantify cause and-effect relationships in the climate system in the future. 
from NOAA
Nonetheless, according to the Fourth National Climate Assessment Volume I and II the impacts of global climate change are already being felt in the United States and are projected to intensify in the future. The severity of future impacts will depend largely on actions taken to reduce greenhouse gas emissions and to adapt to the changes that will occur. Unfortunately, control of global greenhouse gas emissions is not in our hands. The United States represents about 13% of global emissions. In order to avoid exceeding 1.5 degrees C of warming, the recent The Intergovernmental Panel on Climate Change (IPCC) ,the United Nations body for assessing the science related to climate change, says carbon pollution must be cut almost in half by 2030, less than 12 years away, and then reach "net zero" by mid-century. The greenhouse gas emissions from the United States have been decreasing. As you can see below the trajectory of emissions is not good. 
from Oliver et al

The problem is that under the Paris Agreement China has only agreed to stop growing their CO2 emissions by 2030 and the reduction in emissions pledged so far are nowhere near sufficient to hold temperature change to 2 degrees C let along attempt 1.5 degrees according to the climate models.

With China in 2016 as the largest CO2 emitter at slightly more than 26% of the total- twice the United States level, the goals of the Paris Agreement cannot be met without reductions in China and the other nations still growing their emissions and all other nations must increase the level of emissions cut pledged to even meet the 2 degree C goal, let along the aspirational goal of 1.5 degrees C.

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