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NOAA Global Land & Ocean Temperature Chart: May, 2018;
Commentary on Data Collection & Comparison:
One of the most obvious signals of climate change is the rise in global average temperature over the past several decades. Comparing the average temperature of land, ocean, or land and ocean combined for any month or multi-month period to the average temperature for the same period over the 20th century shows if conditions are warmer or cooler than the past.
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How are these data collected?
Temperature data come from manual and automated weather stations. Quality-checked data become part of the Global Historical Climatology Network-Monthly (GHCN-M) data set and International Comprehensive Ocean-Atmosphere Data Set (ICOADS). A combined global land and ocean temperature anomaly dataset was created from these resources.
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GLOBAL GREENHOUSE GAS EMISSIONS  On a global scale, the key greenhouse gases emitted by human activities are:
  • Carbon dioxide (CO2): Fossil fuel use is the primary source of CO2.  CO2 can also be emitted from direct human-induced impacts on forestry and other land use, such as through deforestation, land clearing for agriculture, and degradation of soils. Likewise, land can also remove CO2 from the atmosphere through reforestation, improvement of soils, and other activities.
  • Methane (CH4): Agricultural activities, waste management, energy use, and biomass burning all contribute to CH4 emissions.
  • Nitrous oxide (N2O): Agricultural activities, such as fertilizer use, are the primary source of N2O emissions. Fossil fuel combustion also generates N2O.
  • Fluorinated gases (F-gases): Industrial processes, refrigeration, and the use of a variety of consumer products contribute to emissions of F-gases, which include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6).
Source: Source: IPCC (2014) based on global emissions from 2010. Intergovernmental Panel on Climate Change  via the Environmental Protection Agency U.S.A. January 2017
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June, 2018's global average concentration of atmospheric carbon dioxide (CO2) was about 408 parts per million (ppm)
PictureThe rise in global temperatures since the Industrial Revolution is clearly linked to greenhouse gas emissions/carbon dioxide.


The long lifetime of the gas means it’ll take generations before numbers below 400 ppm are revisited on the way down.
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THE PARIS AGREEMENT - effective 11/7/16
The aim of the Agreement is described in Article 2, "enhancing the implementation" of the UNFCCC through: "
     (a) Holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 °C above
pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change;
     (b) Increasing the ability to adapt to the adverse impacts of climate change and foster climate resilience and low greenhouse gas emissions development, in a manner that does not threaten food production;
     (c) Making finance flows consistent with a pathway towards low greenhouse gas emissions & climate-resilient development."
​Countries furthermore aim to reach "global peaking of greenhouse gas emissions as soon as possible". The agreement has been described as an incentive for and driver of fossil fuel divestment. 
Note Post Election 2017: Although Trump has formally withdrawn the U.S. from the Agreement, many American cities and states pledged to move forward.