IPCC 5th 2014 assessment Food chapter
IPCC 5th assessment 2014  Based on many studies covering a wide range of regions and crops, negative impacts of climate change
​on crop yields have been more common than positive impacts (high confidence) WG2 SPM.

Without (successful) adaptation, local (/global is the same for 1.0C)
​temperature increases in excess of about 1°C above pre-industrial
​is projected to have negative effects on yields for the major crops (wheat, rice  and maize) in both tropical and temperate regions                                                           
(IPCC AR5 WG2  Ch7 Exec Summary p.3 

​​With or without adaptation, negative impacts on average yields become likely from the 2030s with median yield impacts of 0 to –2% per decade projected for the rest of the century, and after 2050 the risk of more severe impacts increases.
​IPCC AR5 WG2 Table 7-3.

September 2014 ​​Scientists on drought:  Scientists warn of 'megadroughts' 

​​Nature March 2014
Climate change will reduce crop yields sooner than we thought.

National Geographic 20 Feb 2014
British Floods, California Drought: A Connection?
A wavy jet stream—and perhaps climate change—underlie recent weather extremes.

​Most are becoming aware that the world is being hit by severely damaging increased extreme weather events. In particular these since 2000 have affected the world's best food producing regions of the Northern Hemisphere (NH).

The evidence amounts to causation since the publication of Potsdam Climate institute 2013 paper amplification of planetary waves and recent Northern Hemisphere weather extremes '​​...  amplification of planetary waves and recent Northern Hemisphere weather extremes' on the NH climate dynamics at work. 

​​We are already committed due systemic inertias to a global warming above 2.5C and on our current world economy at mid century.

​​Increasing world drought (especially N. hemisphere) has resulted in a global water crisis that is causing world grain reserves to fall and global food prices to become volatile. This in turn is causing a committed increasing global food crisis that is a global emergency (Center for Climate & Security Jan 2013)

Evidence suggests world drought has been increasing  driven by global temperature increase as expected. Since 2000 the record shows an extraordinary increases in Northern hemisphere heat and drought. Today  (Dec 2012) central US (great grain belt) in a three increasing year drought predicted to persist the April 2013.

In particular over the past decade, and 2012 especially, all the world's top food producing regions in the North hemisphere are being hit by drought. ​​

​​21 August 2012 – "More consolidated efforts to combat the threat of climate change and counter its ripple effects on global food security are needed amid an intensifying global drought and increasing temperatures worldwide," the United Nations declared today.

​With drought intensifying worldwide, UN calls for integrated climate policies.

​"Climate change is projected to increase the frequency, intensity, and duration of droughts.

One quarter of the United States was experiencing exceptional drought while the entire country was facing its longest 12 month period in a drought since 1895."

India is "similarly experiencing a very serious droughts with countrywide rainfall of 17 per cent below normal. In Punjab, India’s breadbasket, rainfall was 70 per cent below normal."

According to the WMO, "severe drought also developed in parts of East Africa in late 2010 and continued through most of 2011 with the most severely affected areas encompassing the semi-arid regions eastern and northern Kenya, western Somalia, and southern border areas of Ethiopia.

In 2009, international climate experts gathered at the International Workshop on Drought and Extreme Temperatures in Beijing released their climate projections for the 21st century, forecasting an increase in the frequency of severe droughts in the continental USA and Mexico, the Mediterranean Basin, parts of northern China, across southern Africa and Australia and in parts of South America."
The world's best food producing regions ​are in the Northern Hemisphere (NH)


10 Oct 2019 Billions face food, water shortages over next 30 years as nature fails
10 Dec 2019.  Jet stream changes -hit global breadbaskets
August 2019 Quarter of Humanity Faces  Water Crises
23 Jan 2017 Most important assessment FAO-IPCC
Projected productivity changes and extreme events 1.1.1 Crops
In terms of global temperature and the yield response curves for crops such as wheat and maize,..
is that a 1 or 2 ºC warming to increase yields in temperate regions is no longer expected
8 Mar 2021. Food systems are responsible for a third of global anthropogenic GHG emissions UN, FAO, Nature Journal
8 April 2021,  Study calls for urgent climate change action to secure global food supply
Word doc of Multiple adverse impacts  in above review paper
IMPORTANT RESEARCH, 2020 Maximum warming and related to crops
1 November 2021,Climate impacts on global agriculture emerge earlier in new generation of climate and crop models
1 Feb 2022.  Phasing out animal agriculture could stabilize greenhouse gas levels for decades  

Extreme weather is increasing, and is most damaging to populations and crops.
March 2023, M. Heino Increased probability of hot and dry weather extremes during the growing season threatens global crop yields​
IPCC 2019 Land Report